Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
231 In certain plausible energy futures, driving could become much cheaper on a per-mile basis. This would support higher growth in vehicle miles of travel for both cars and trucks, in turn leading to greater traffic congestion and possibly more vehicle crashes and fatalities. This appendix discusses several potential strategic directions aimed at mitigating traffic con- gestion, either by investing in new road capacity or managing existing capacity more efficiently, or by improving traffic safety, with additional benefits for cyclists and pedestrians. Note that strategies with the primary aim of improving alternative modes of travel, such as transit, biking, and walking, could also play some role in mitigating traffic congestion; such strategies are discussed in Appendix L. The strategic directions reviewed in this appendix include expansion of road capacity, goods movement investments, congestion pricing, ITSs, TSM&O, and traffic safety measures. K.1 Road Expansion Under this strategy, states would focus on expanding highway capacity as a principal response to mounting traffic congestion in urban and suburban areas, as well as to provide enhanced mobility in rapidly developing areas. This would require significant financial resources; as such, pursuit of this strategy would likely require that a state also take steps to increase available transportation funding through one or more of the strategies discussed in Appendix I on revenue strategies. K.1.1 Supportive Policies The addition of new capacity could take the form of add- ing additional lanes to existing routes or building entirely new routes. Adding capacity to existing routes. In urban areas and in many suburban areas, the road network is already dense, and much of the surrounding land is well-developed. In such instances, the provision of additional road capacity usually translates to adding more lanes to existing routes. Other types of improvements, such as the construction of over- or under- passes for grade-separated interchanges, can also increase the effective throughput capacity of a route. Building new routes. In developing areas where the road network is less dense and much of the surrounding land is undisturbed, the construction of entirely new routes may offer greater transportation benefits than the expansion of existing routes. Assumed policies for assessing road building. In assess- ing the potential effects of this strategy, it is first assumed that a state would take steps to boost transportation revenueâfor example, through increased fuel taxes, higher vehicle registra- tion fees, or mileage-based road-use fees. With the necessary funding in place, the state would then seek to add lanes to exist- ing routes that are chronically congested and build new routes in areas of rapid growth, as appropriate. The ratings for this strategy assume that a state would not implement conges- tion tolling for the purpose of using existing or newly added capacity as efficiently as possible; that option is considered as a separate strategy later in this appendix. On the other hand, the assessment does assume that states would only invest in new capacity in cases where benefitâcost analysis indicates a strong return on investment. K.1.2 Intended Mitigation Effects Taking stock of the potential impacts under various energy futures, the main intent of building more roads would be to help ease traffic congestion. Reducing traffic congestionâmoderately effective. Traffic congestion occurs when the number of vehicles trying to use a route exceeds the capacity of that route. This is most com- mon during morning and afternoon peak periods, although so-called nonrecurrent traffic congestion can also arise due to traffic incidents, construction activities, severe weather, special events, and the like. Building new capacity has the effect A p p e n d i x K Strategies to Improve Auto and Truck Travel
232 of increasing the ratio of the available road space to the num- ber of vehicles traveling in a corridor, in turn reducing traffic congestion. Over the short term, congestion reduction can be dramatic. Over the longer term, however, as more vehicles begin to use the route due to latent and induced demand, congestion often returns to previous levels. Downs (2004) describes this common phenomenon as âtriple convergence.â In essence, traffic is already so severe in many metropolitan areas that numerous travelers routinely go out of their way to avoid peak-hour travel in the most congested corridors. Instead, they travel at less convenient times, select less con- venient routes, or choose less convenient modes of travelâ all to avoid sitting in traffic congestion. When adding road capacity leads to a reduction in peak-hour congestion, how- ever, travelers will soon learn of the improvement. As they observe traffic flowing more freely, they will return to peak- hour useâconverging from other times of travel, routes of travel, and modes of travelâslowly undermining the initial congestion-reduction benefits. Given this effect, road build- ing is rated as being only moderately effective in reducing congestion over the long term. K.1.3 Intended Shaping Effects The strategy of building more roads would not be expected to exert significant influence on the types of fuels and vehicle technologies used in the transportation sector. K.1.4 Other Effects Beyond its potential effects in reducing congestion, road building can also play a role in enhancing economic pro- ductivity and growth. At the same time, it may have negative implications for the environment and equity. Economyâmoderately positive. Throughout the his- tory of the United States, investments in transportation infrastructureâthe Erie Canal, the Transcontinental Rail- way, and the Interstate system, to name a few prominent examplesâhave created the basis for continuing growth and prosperity. Even today, with a road network that is already extensive, investment in new routes or additional lane capac- ity can create jobs in the short term and support a stronger economy over the longer term. This is because well-selected road investments allow goods and services to be transported quickly and at lower cost, resulting in both lower prices for consumers and increased profits for firms (U.S. Department of the Treasury and U.S. Council of Economic Advisors 2012). While in some cases road investment has the effect of attract- ing economic activity that otherwise would have occurred elsewhere, a recent analysis of the literature indicated that investing in highway capacity remains generally positive for net economic growth (Shatz et al. 2011). With that in mind, the main reason that this strategy is rated as being only mod- erately positive with respect to the economy is that it does not ensure that road capacity, new or existing, will be used as efficiently as possible. To maximize the economic productiv- ity of the road network, congestion pricing, as discussed later in this appendix, would be even more effective. Environment and public healthâmoderately negative. By easing traffic congestion, investments in new road capacity can reduce emissions per vehicle mile of travel. On the other hand, new capacity also accommodates a greater amount of total travel. And, as described previously, the effects of triple convergence tend to erode the congestion-reduction benefits of new capacity over the long term. Finally, any new roads built in previously undeveloped areas could lead to loss of habitat and open space. Turning to public health, more high- way investment could lead to more driving and less transit use, walking, or biking. On balance then, the environmental and public health effects can be generally characterized as negative overall. Equityâmoderately negative. Because of both noise and pollution, home values in areas immediately adjacent to free- ways tend to be lower than in other areas. As a result, such areas are more likely to be populated by residents with lower incomes and other disadvantaged groups. Any of the negative local effects of expanding freeways are therefore likely to be concentrated among these groups as well, with negative impli- cations for equity and environmental justice (Deka 2004). K.1.5 Barriers Financial constraints represent the main barrier to signifi- cant road expansion, although some degree of public opposi- tion is likely as well. Incidentally, these two factors are cited by Brown, Morris, and Taylor (2009) as the main reasons for the decline in freeway building in this country since the 1960s. Low public supportâmoderate barrier. Due to the poten- tial concentration of negative effects on lower-income and minority groups living near freeways as well as the more gen- eral adverse effects of emissions and loss of undeveloped land, efforts to add lanes to existing freeways or build new routes are often opposed by social justice advocates and environmental proponents (Brown, Morris, and Taylor 2009). The process of environmental review affords such groups the opportunity to challenge major infrastructure projects in court, potentially delaying or even preventing their completion. Financial costâsignificant barrier. Building new road capacity is expensive. As a base estimate, the American Road and Transportation Builders Association (ARTBA) suggests a cost of about $1 million to $1.5 million per lane mile in rural areas and about $2 million to $2.5 million in urban areas (ARTBA 2012). However, construction costs have been ris- ing more rapidly than general inflation over the past decade
233 due to greater global demand for resources. Additionally, some projects can be far more expensive than the base costs listed by ARTBA. Factors that can contribute to higher costs include the need to tunnel or elevate structures and the need to acquire additional right-of-way that has already been devel- oped, especially in urban areas with higher property values. As an illustration of how expensive a road expansion project can be, the cost of adding a single HOV lane on a 10-mile stretch of the I-405 freeway over the Sepulveda Pass in Los Angeles was $1.03 billion [LACMTA (Los Angeles County Metropoli- tan Transportation Authority) and Caltrans, undated], trans- lating to over $100 million per mile. Finally, any new lane mile that is constructed will also need to be maintained over time, adding to the ongoing demands on a state DOTâs budget. In short, building new road capacity is an expensive proposition; given that many states are already facing severe budgetary shortfalls, increasing revenue would be a necessary precursor to aggressive pursuit of this strategy. K.1.6 Required Lead Time Building or expanding roads entails a long process that includes planning, financing, detailed engineering, environ- mental review, and construction. While smaller projects could be completed in the 5- to 10-year time frame, larger projects are likely to take 10 to 20 years, or in some cases (e.g., where there is significant opposition and litigation) even longer. K.1.7 Qualifications This strategy could be most helpful in states or regions that are experiencing rapid growth. It is also likely to be easier and less costly in suburban and exurban areas than in dense urban locales. K.2 Goods Movement Improvements State DOTs are increasingly broadening the scope of proj- ect activities and expanding institutional roles to better sup- port goods movement. In the past, freight has often been overlooked and underfunded in state planning processes. More recently, there has been renewed interest in the eco- nomic development potential of major international trade gateways and regional freight hubs, greater awareness of the environmental benefits of facilitating intermodal system effi- ciencies, and direct interest in strategies to shift truck travel off of major corridors and out of urban areas. As a result, states are pursuing broad, coordinated strategies to facili- tate goods movement by engaging in projects and activities, often in cooperation with the private sector, to increase sys- tem efficiency and expand capacity. Intended outcomes can include enhancing economic development, reducing traffic congestion and delay, improving air quality and in turn pub- lic health, and enhancing travel safety and domestic facility security. K.2.1 Supportive Policies The approaches included in this strategy focus on support- ing truck and rail freight movements, although sea and air modes are closely connected and also planned for by states in some cases. The overall objective is to enable more efficient goods movement, thus reducing impacts on shared infra- structure such as state highways. Truck efficiency and capacity expansion. In recognition of the economic importance of goods movement and the parallel need to mitigate the negative impacts of heavy truck traffic on urban areas, regional corridors, and the Interstate system, many states are now focusing more on freight planning issues in general, and especially on truck travel. One option is to focus on roadway improvements designed to increase the connectivity to multimodal terminals, to major industrial areas, or between corridors. Often such road access is older and more constrained, traversing areas never designed for the larger equipment and heavier volumes of today. As a result, minor improvements in turning lanes, road width, interchange design, pedestrian overpasses, and other design features can offer significant improvements for truck movements. The ConnectOregon program, for example, is a lottery-bondâ based initiative that generates revenues for investments in air, marine, rail, and transit infrastructure; freight-related investments are intended to improve connections between the highway system and other modes of transportation to facilitate the flow of commerce and reduce delay. States are pursuing other activities such as truck-only toll lanes and new corridor development to add capacity spe- cifically for goods movement. A related option is to modify vehicle size and weight restrictions to facilitate more efficient truck operations (Cambridge Systematics 2009). Finally, some states are also supporting the development of statewide freight planning, investing in better commercial freight data collec- tion and analysis, or developing freight corridor plans and programs. In Washington State, the Freight Mobility Strategic Investment Board offers freight-specific project prioritiza- tion at the state level, while the Freight Action Strategy for the EverettâSeattleâTacoma Corridor partnership improves pub- lic and private freight stakeholder coordination in the Puget Sound region (Washington State DOT 2008). Rail efficiency and capacity expansion. Some states have also begun to commit public funding, in partnership with private rail operators, to support rail projects intended to relieve congested choke points and bottlenecks along major rail corridors or to improve access to major inland hubs and seaports. These actions reflect recognition of the need for
234 DOTs, for example, are piloting truck-stop and rail corridor electrification projects to reduce emissions and create idle- free zones. The Port of Long Beachâs (POLB) Clean Truck program restricts vehicles not meeting 2007 federal emis- sions standards from accessing the port (POLB, undated). Urban freight consolidation and pickup centers, intermo- dal hubs, and information systems are increasingly attracting attention as ways to reduce local delivery truck congestion in urban areas. Given the energy and emissions advantages of rail freight, more states are considering strategies to facilitate mode shifts from truck to rail as well. Assumed policies for assessing DOT involvement in goods movement. The strategy assessments that follow assume that a state DOT would pursue a coordinated set of freight opti- mization strategies designed to reduce delays, improve system efficiency, and produce environmental benefits. To support these activities, the state DOT would expand its role in freight planning, prioritize freight project funding, and engage in new partnerships and institutional arrangements. The assessments also assume that a state would take steps to boost transporta- tion revenue, through one or more of the options discussed in Appendix I, to allow for greater investment in freight-related projects. K.2.2 Intended Mitigation Effects Increasing DOT support for goods movement is likely to produce modest reductions in traffic congestion, improve- ments in safety outcomes, and some environmental benefits. Reducing traffic congestionâmoderately effective. Many bottleneck relief and capacity-expansion projects are aimed at reducing traffic congestion. In areas with high volumes of freight flow by rail or truck, targeted infrastructure improve- ments can result in significant congestion relief. For example, Southern Californiaâs Alameda Corridor project illustrates how improved freight flows through a local bottleneck affect destinations well beyond the immediate project area. The Alameda Corridor project is estimated to have significantly reduced congestion on rail connections between the ports of Los Angeles and Long Beach and the rest of the nation and to have eased local traffic congestion in the Los Angeles area on streets that formerly crossed the railroad at grade (Alameda Corridor Transportation Authority 2012). The strategy is only rated as being moderately effective at reducing traffic congestion, however, for two reasons. First, its effects will tend to be limited to areas or corridors with high levels of trucking activity rather than helping to reduce traffic con- gestion more broadly throughout entire metropolitan areas. Second, to the extent that traffic congestion is reduced, the improvement in traffic conditions may attract additional peak- hour trips resulting from latent or induced demand, eroding some of the benefits over the longer term (Downs 2004). states to play a greater role facilitating freight mode shifts from truck to rail in order to reduce interstate congestion and better use capacity on existing systems. Additional moti- vations are renewed interest in seaports and rail terminals as drivers of economic development and in the energy and environmental efficiency of rail options. System efficiency and expansion projects include capacity investments that improve connections of rail lines to terminals and seaports or roadway overpass and grade crossing separation redesigns to allow for double-stack containers or more direct rail ser- vice; grade separation projects can also play an important role in reducing traffic congestion on roads in the surround- ing area. Many states are also expanding state loan programs or dedicating transportation funds typically reserved for highways to rail programs. For example, the State of Dela- ware recently funded rail bridge improvements to the Port of Wilmington. The Norfolk Southern Railroad will repay the state over 20 years through a toll on each railcar passing over the bridge. Missouri DOT has funded two railroad overpasses to eliminate bottlenecks in one of the most heavily used rail hubs in the country. Washington State DOT has committed $400 million to improve rail access and egress to the ports of Seattle and Tacoma (Horsley 2006). Freight management and commercial vehicle operations. Advanced technologies are also being applied to better man- age freight movements and reduce delays across modes. Auto- mated pre-pass and weigh-in-motion screening systems, for example, help reduce unnecessary stops for trucks. Transpon- ders on freight containers and automatic vehicle identification systems are also in use at border crossings and ports of entry to speed transit time and address security concerns. The Cross- Town Improvement Project in Kansas City, for example, was introduced to improve the efficiency of regional freight move- ment. This program included the development of an Inter- modal Move Exchange (IMEX) database, designed to increase communication and coordination among truck, rail, and ter- minal operators with the goal of maximizing loaded moves and minimizing unnecessary return or empty trips. As a result, regional intermodal trips fell 22% in the Kansas City region, and significant reductions in cross-town and local delivery trips were achieved (Delcan Corporation 2007). Systems such as IMEX can be described as open-architecture information systems that use communications technologies and real-time information to improve freight logistics and travel patterns. Multimodal freight policies to improve environment performance. DOTs may also pursue freight-related activities with the intent of mitigating environmental impacts associ- ated with goods movement. States support projects and activi- ties such as idle-free zones, truck-stop electrification, clean fuel and vehicle standards, vehicle equipment design, and active system management technologies to reduce the air quality impacts of goods movements. The Oregon and Connecticut
235 a port connector facility, could provide significant economic development and trade benefits to regional economies. Environment and public healthâmoderately positive (uncertain). Some of the policies included here, such as the electrification of rail lines and idle-free zones for truck stops, are intended principally for their air quality benefits, with positive environmental and public health outcomes. Policies under this strategy should also improve safety, which can be viewed as beneficial from a public health perspective. Still other policies are aimed at greater efficiency in goods movementâfor example, by eliminating empty truck trips, by reducing delays, and by encouraging multimodal transfer and mode shift to rail. These improvements are also likely to result in air quality benefits at local and regional scales. Improved efficiency, however, could lead to greater overall vehicle travel over the longer term, either from latent pas- senger vehicle demand that emerges as congestion is reduced or from increased demand for longer-haul trips as freight logistics costs decrease. Taking all of these factors into con- sideration, the environmental and public health impacts of this strategy are judged as moderately positive but uncertain. Equityâneutral (uncertain). While policies for improv- ing goods movement raise some equity concerns, it should be possible to mitigate these to a large degree by prioritizing the inclusion of environmental improvement projects, as has been assumed here, and by choosing appropriate revenue sources to fund improvements. Regarding the first of these, goods movement facilities and rights-of-way are historically located on commercial or industrial land often abutting low- income neighborhoods. Residents in these areas have suffered the brunt of the negative impacts associated with goods move- ment, including worsening traffic, harmful air pollution, and noise. These impacts can be mitigated through such policies as requiring cleaner trucks in port areas, idle-free truck stops, elec- trified rail, and reduced empty return truck trips. Regarding the second issue, appropriate funding sources, goods movement improvements can offer both public and private benefits. Care- ful analysis is therefore warranted in determining who should pay, and how much, for such investments. As a general rule, though, user feesâsuch as weight-distance truck tolls on the road network and container fees at portsârepresent an equi- table means of raising funds that also encourages more efficient use of the system (NSTIFC 2009). K.2.5 Barriers Financial cost represents the most significant barrier for this strategy, although some institutional restructuring may also be needed for a state DOT to take a more active role in planning and funding goods movement improvements. Financial costâsignificant barrier. The question of how to fund and finance freight transportation projects has been Improving safety outcomesâmoderately effective. To the extent that freight management and roadway system improve- ments reduce congestion, there will be safety improvements associated with minimizing commercial and passenger vehi- cle incidents. In addition, roadway design improvements, such as pedestrian overpasses, eliminating at-grade crossings, inter- change designs, and truck-only lanes, will produce immediate safety benefits, particularly in areas surrounding ports and terminals. Management systems and operational improve- ments are also stressed because of the safety and security improvements offered, particularly to address domestic secu- rity concerns for ports of entry and high-value infrastructure and facilities. Improving air qualityâmoderately effective. Shifting significant freight volume from truck to rail, reducing bottle- necks and congestion on major corridors, minimizing stops and delays, and routing goods through consolidation centers and inland ports should all result in more efficient freight movements and, in turn, improved air quality. Other projects, such as rail corridor or truck-stop electrification, are specifi- cally aimed at improving local air quality, especially in non- attainment areas. The effects of goods movement projects on air quality can be quite significant; in the case of the Port of Long Beachâs Clean Trucks program, for example, qualifying trucks (those that meet or surpass the 2007 federal emissions standards) are estimated to produce 80% less pollution than older models (POLB, undated). K.2.3 Intended Shaping Effects These strategies are mainly intended to mitigate the adverse impacts associated with the potential for continued growth in truck travel and goods movement rather than to shape spe- cific fuel and vehicle technologies. K.2.4 Other Effects In terms of broader effects, this strategy is likely to be quite positive for economic growth, moderately positive with respect to the environment, and neutral from an equity perspective. Economyâhighly positive. Freight movement plays a critical role in the national economy, and any improvements in the efficiency of the transportation system should trans- late to productivity gains for the trade, logistics, warehousing, and wholesale industries, ultimately translating to lower costs for other businesses and consumers. Congestion delays are a major source of economic loss for freight shippers and whole- salers, and they affect inventory costs and consumer prices. Improvements in the fuel economy of vehicles and trains based on reductions in congestion delays are also likely to pro- duce returns for freight shippers. Larger-scale, catalytic invest- ments, such as a major rail grade separation or investment in
236 often controversial tool for reducing traffic congestion, gen- erally in urban areas or along specific corridors. K.3.1 Supportive Policies To date at least four broad forms of congestion pricing have been implemented or considered. These are facility- based congestion tolls, cordon or area pricing, network-wide congestion pricing, and parking pricing. Facility-based tolls. Facility-based tolls have two distinct configurations: full-facility congestion tolls, in which all users of a facility (e.g., a bridge, a tunnel, or a stretch of highway) pay tolls that are differentiated by time of day; and managed lanes, in which only a subset of the lanes of a facility are priced. The latter gives drivers a choice between paying for a faster trip in the less-congested lanes and continuing to use the more- congested general-purpose lanes for free. In the United States, full-facility congestion tolls have only been implemented on routes that were already subject to tolls. In switching from a flat toll structure (i.e., the same toll rate at all times of the day) to a variable toll structure, it is possible to decrease the off-peak toll or increase the peak toll (or both). In Fort Myers, Florida, a discounted toll rate was offered just before and just after peak hours; this change encour- aged many drivers to switch to driving during off-peak hours (FHWA 2008a). In 2000, the New Jersey Turnpike Authority introduced electronic toll collection (ETC) along with tolls that varied by time of day as well as by method of payment (cash versus ETC). The ETC off-peak toll remained the same as it had been previously, while the toll rates for peak-period use and cash payments increased. Currently there are at least nine examples of full-facility congestion tolls operating in the United States, with several others in the planning stages (FHWA 2012b). Managed lanes, including HOT lanes and express lanes, have been the most popular approach to congestion pricing in the United States because they offer drivers a choice of pay- ing extra for a faster drive when needed but still maintain the option of traveling in the general-purpose lanes for free. In the HOT lanes approach, the extra capacity in preexisting or newly constructed carpool lanes is made available to solo driv- ers willing to pay a toll for faster travel; to ensure that the lanes remain free-flowing, the toll rate for solo drivers increases as the lanes become more crowded. To date, HOT lanes have been implemented in California (I-15 in San Diego and I-680 in Alameda County), Colorado (I-25 and US-36 in Denver), Florida (I-95 in Miami), Georgia (I-85 in Atlanta), Minnesota (I-394 in the Twin Cities), Texas (I-10 and US-290 in Hous- ton), Utah (I-15 in Salt Lake City), and Washington (SR-167 in Seattle). Express lanes are similar in concept to HOT lanes, with the toll rate varying to maintain a high level of service even during peak periods. The main difference between HOT lanes a topic of increasing interest at the local, state, and federal levels. Traditionally, most freight system improvements have been funded by the private sector, with minimal involvement from the public sector. However, many states are now begin- ning to provide some assistance in the funding of freight- specific improvement projects. The sheer size and cost of many of these projects, as well as the necessary involvement with private-sector freight partners, often mean that states and regions must draw on a wide range of sources to fund and finance freight improvement projects. State infrastructure banks, other loan assistance programs, and matching funds programs are being used to help offset the high up-front capi- tal costs of these projects. Other projects are being funded with direct user fees generated from mechanisms such as truck-only tolls, weight-distance taxes, and per-carload or port entry fees. Institutional restructuringâmoderate barrier. Recog- nizing that freight trips typically involve greater transport distances across more jurisdictions than passenger trips, states and freight stakeholders must form coalitions and part- nerships at increasingly large scales to plan for goods move- ment. Current examples of multi-state and multi-stakeholder partnerships exist at the regional, mega-regional, and cross- continental or international levels. The resources, institu- tional arrangements, and additional activities required of states involved in coordinated freight planning could present a moderate barrier. K.2.6 Required Lead Time While smaller-scale freight-related projects could be com- pleted more quickly, larger-scale corridor developments or more ambitious programs, such as truck-only toll lanes, are likely to require considerable lead time to finance, plan, design, and construct. As a result, the time frame required for a DOT to assume a greater role in goods movement and fully imple- ment a comprehensive set of freight optimization strategies is estimated to fall in the range of 10 to 20 years. K.2.7 Qualifications Given that all states have at least some goods-movement activities, this strategy should be helpful in all states. However, it would offer the greatest benefits in states with major port facilities, intermodal facilities, or goods-movement corridors. K.3 Congestion Pricing Congestion pricing is a road pricing strategy in which tolls or charges differ by time of day to provide a financial incen- tive for drivers to shift some of their trips from peak to off- peak periods. Congestion pricing has proven a potent though
237 Parking pricing. The concept of congestion pricing can also be applied to rates for on-street parking, as described by Shoup (2005). Many cities routinely underprice their curb parking spaces in relation to demand, resulting in a chronic scarcity of available spaces. Because the prices are so low, drivers have an incentive to circle around the block searching for an available spaceâdescribed as âcruising for parkingââ rather than paying higher rates for private off-street park- ing. This behavior, which can result in significant additional traffic congestion in busy commercial districts, wastes time, wastes fuel, and produces excess greenhouse gas and local air pollutant emissions. The solution proposed by Shoup is to vary parking meter rates throughout the day in accordance with prevailing demand conditions with the goal of achieving a parking space occupancy rate of roughly 85%âthat is, ensuring that there are usually one or two open curbside spaces on any block (assuming that a typical block has about 10 curbside spaces). Achieving this goal would make the process of parking much more convenient for visitors to an area, reduce congestion, and eliminate the extra time, fuel consumption, and emissions that result from cruising. Simultaneously, it would result in greater parking revenue for municipalities. To date, variable curb parking rates have been implemented in New York City, Washington, D.C., San Francisco, and other cities. Although states cannot directly implement street parking reforms, a state DOT could offer technical support, encouragement, and even incentives for cities wishing to pursue such a policy. Assumed policies for assessing congestion pricing. HOT lanes have proven both successful and popular wherever imple- mented, and many more are currently in the planning stages. To date, though, their application has been limited to either exist- ing HOV lanes with excess capacity or to new lane construc- tion. However, because there are many congested freeways that lack HOV lanes and lack sufficient rights-of-way to construct new lanes, the potential for further expansion of the HOT lanes concept is ultimately constrained. For this assessment, a more ambitious approach to congestion pricing is considered where states would establish some form of managed lanes on all congested highway routes. In many cases, this would require the conversion of one or two existing general-purpose lanes to priced lanes, an idea likely to prove controversial. This would most likely occur in concert with a switch from fuel taxes to some form of electronic tolling or MBUF to raise highway rev- enue since either of these could provide the underlying technol- ogy able to support such a broad application of congestion tolls. The assessment does not assume the implementation of cordon tolls, network-wide congestion pricing (i.e., including arterials along with freeways), or variable parking pricing because any of these would likely be initiated by local jurisdictions. A state could, however, provide assistance and technical support for any such efforts on the part of local decision makers. and express lanes is that all vehicles, including carpools, must pay for express lane tolls. By this definition, SR-91 in South- ern California is the only current example of the express lanes approach. As noted by Poole (2012), many more HOT lane and express lane projects are currently in the planning stages. Cordon pricing. With a cordon congestion toll, vehicles must pay a fee to travel within a congested area (typically a central business district or urban core) with a clearly defined boundary (the cordon line) during peak hours. Depending on implementation details, the toll may be incurred when the vehicle is observed to be traveling within the zone (often referred to as an area licensing scheme) or when the vehicle crosses the boundary into or out of the zone. In the latter case, a vehicle may be assessed the toll at most once per day or, alternatively, may be assessed the toll each time it crosses the boundary (up to some maximum number of times per day), and the toll rate may be structured to vary by both time and location of entrance or exit. The most well-known examples of cordon tolls are in Singapore, London, and Stockholm. Although Singapore initially began with a paper-based area licensing scheme in the 1970s, it switched to an all-electronic tolling system in the late 1990s and is now the most advanced program in terms of varying the toll rate by time and loca- tion around the charging zone to optimize flow rates in dif- ferent areas throughout the day (Goh 2002, Fabian 2003). No cities in the United States have yet implemented a cordon toll to reduce urban traffic congestion, although both New York City and San Francisco have studied the concept. The plan in New York was nearly implemented but ultimately failed to gain enough support in the state legislature. The concept has been implemented, however, to help control truck traffic at the ports of Los Angeles and Long Beach. Under the PierPASS program, trucks that pick up or drop off loads during a defined set of peak hours must pay a fee of $60 per 20-foot container or $120 for any other size container; the fee does not apply for trucks that visit during off-peak hours (PierPASS undated). Network-wide congestion pricing. Under network-wide congestion pricing, all vehicles traveling on the network of major routes (e.g., highways and major arterials) within a city or region would pay variable congestion tolls based on time of day, route, and distance traveled. Singaporeâs electronic road pricing (ERP) system approaches this idea. In addition to the cordon toll charged for entering the central business district, the Singapore system also includes gantries set up on highways and major arterials in the broader metropolitan region to assess tolls for traveling during peak commuting hours. No other such system has been implemented, but the Puget Sound region has conducted field trials of this con- cept (Puget Sound Regional Council 2008) and subsequently proposed, in its most recent long-range plan, Transportation 2040, to use congestion pricing on most of its major highways and arterials to both manage congestion and raise revenue.
238 peak-hour travel on the SR-91 express lanes, per data reported by Obenberger (2004), traffic speed in the priced lanes aver- aged 60 to 65 miles per hour, while traffic speed in the adja- cent heavily congested general-purpose lanes averaged just 15 to 20 miles per hour. When Singapore upgraded to its ERP system for congestion pricing in the 1990s, peak-hour travel speed in the central business district (CBD) nearly doubled to 36 km per hour, while peak-hour travel speed on the radial expressways approaching the CBD increased from 45 to 65 km per hour (Goh 2002). Early results in London were similarly impressive. After launching the central charging zone, conges- tion delays within the zone were reduced by 30%, travel speeds within the zone increased by 21%, and travel speeds from outer London to the zone increased by 12% (Santos and Shaffer 2004). Another particularly valuable attribute of congestion pric- ing as a means of reducing traffic congestion is that it will remain effective indefinitely provided that the charge rates are allowed to vary with changes in demand. This is not the case with most other congestion-reduction strategies pursued in the past. The basic challenge is that traffic is already so severe in most metropolitan areas that many travelers choose to avoid peak-hour vehicle travel in congested corridors whenever pos- sible. They may, for example, travel at different times of day, by different routes, or by different modes. When an invest- ment is made to reduce traffic congestion within a corridorâ such as adding a lane to an existing freeway or building a new transit line that is successful in luring some drivers from their carsâthe flow of traffic may be significantly improved over the near term. Over the longer term, however, travelers who had taken steps to avoid severe peak-hour traffic will learn of the improved conditions and adjust their tripsâshifting back from other modes, routes, or times of dayâto take advan- tage of the faster peak-hour traffic flow. This phenomenon, described by Downs (2004) as âtriple convergence,â tends to slowly but steadily erode the benefits of most traffic reduction investments within a few years. A critical benefit of congestion pricing is that it is the only strategy for reducing traffic congestion that resists the effects of triple convergence. This is because the imposition of the congestion chargeâagain assuming that it is structured to fluctuate with demandâserves as an ongoing deterrent that acts to prevent excessive use of a facility during peak hours. Over a period of several decades now, Singaporeâs continued application of congestion tolls to reduce traffic in and around the central business district has experienced ongoing success (Olszewski 2007). A final point is that the application of congestion pricing for a subset of lanes on all crowded freeways, as envisioned in this assessment, could actually help reduce congestion on parallel untolled routes as well. This may seem counterintui- tive at first given that congestion tolls are likely to induce some drivers to choose an alternate facility. One of the benefits of K.3.2 Intended Mitigation Effects While the main intent of congestion pricing would be to reduce traffic congestion and offer a choice of faster travel in the priced lanes, the strategy could offer several other impor- tant benefits such as increased revenue, reduced DOT costs, improved safety outcomes, and support for alternative modes of transportation. Increasing transportation revenueâhighly effective. While it is difficult to provide a general estimate of how much additional revenue might be raised through congestion pric- ing on the highway network within a state, there is reason to believe that it would be substantial. The following examples help illustrate the potential revenue effects of congestion pricing. The Singapore ERP system, which includes both congestion tolls on major routes approaching the central busi- ness district along with a cordon congestion toll, grossed about $90 million and netted $72 million (both in U.S. dollars) in 2008 (Arnold et al. 2010). On the I-15 HOT lanes and SR-91 express lanes in Southern California, peak-hour congestion toll rates approach a dollar per mile; by contrast, California fuel taxes (at 18 cents per gallon) cost drivers in the state a little less than a penny per mile on average. A recent congressional commission study estimated that the revenue raised by tolling highways across the country (including base tolls and, pos- sibly, congestion tolls) could range between $22 billion and $105 billion, comparing favorably with the roughly $35 billion currently generated by federal fuel taxes and other sources of HTF revenue (NSTIFC 2009). Reducing DOT costsâhighly effective. Roads can accom- modate greater vehicle throughput when traffic is flowing smoothly than when traffic is heavily congested. During peak hours on the SR-91 express lanes in Southern California, for example, the congestion-tolled lanes serve almost twice the number of vehicles per lane per hour as the heavily congested general-purpose lanes (Obenberger 2004). Broad application of congestion pricing to maintain free-flowing traffic condi- tions should therefore enable more efficient use of existing capacity, in turn lessening the need for DOT investments in new capacity. Reflecting this potential, a recent Conditions & Performance report from the FHWA estimated the costs of maintaining or improving the nationâs road network both with and without congestion tolls (FHWA 2010). The find- ings were dramatic. In the absence of congestion tolling, the cost of improving the Interstate system for projects with a benefitâcost ratio of at least 1.5 was estimated at $47 billion. With the addition of congestion tolls, and again using a benefitâcost ratio of 1.5, the cost of improving the Interstate system would decrease to just $24 billion (Poole 2010), nearly a 50% savings. Reducing traffic congestionâhighly effective. This is the main goal of congestion pricing, and evidence shows it can be very effective in this regard. For example, during
239 Barth and Boriboonsomsin (2007) found that per-mile emis- sions are lowest for travel speeds in the range of 40 to 60 miles per hour and much higher under more congested conditions. Enhancing non-automotive travel optionsâhighly effec- tive (uncertain). Congestion pricing could improve transit and other non-automotive travel options in two ways. First, any improvement in travel speeds will also help make bus tran- sit faster. With implementation of the ERP system in Singapore, for example, the reduction in traffic congestion allowed for an increase in bus speeds of 16% (Goh 2002). In London, bus delays within the charging zone were reduced by about 30% (Santos and Shaffer 2004). Such gains, combined with desire to avoid the congestion charge, have translated to increased rider- ship. In Singapore, the mode share for bus transit traveling into the charging area increased from 30% to 46% (Willoughby 2000). In London, peak-period bus ridership increased by 38% (TfL 2008), while overall transit use in Stockholm increased by about 6% (City of Stockholm 2006). Second, congestion pricing revenues are often, though not always, directed to transit improvements in the region. Pro- viding improved travel options to those unwilling or unable to pay the congestion tolls can help mitigate equity concerns commonly associated with congestion pricing (Ecola and Light 2009). In the case of the I-15 HOT lanes in San Diego, for example, the modest net operating proceeds are used to help subsidize express bus service in the corridor. In London, where the net revenue stream is several orders of magnitude greater, all proceeds have been devoted to significant bus ser- vice improvements along with enhanced bicycle and pedes- trian infrastructure (TfL 2008). Revenue from the Singapore ERP system, in contrast, is channeled into the general fund. In a more democratic society such as the United States, the political calculus of congestion pricing suggests that a size- able share of the revenue resulting from broader adoption of congestion pricing revenue would likely be devoted to transit improvements to offset equity concerns. K.3.3 Intended Shaping Effects While the main objective of congesting pricing is not to influence energy use patterns, it could play a modest role in reducing oil consumption and the energy cost of travel. Reducing oil consumptionâmoderately effective (uncer- tain). Vehicle fuel economy degrades significantly in highly congested traffic conditions (Barth and Boriboonsomsin 2007). By promoting more smoothly flowing traffic, con- gestion pricing could improve the average fuel economy of vehicles in use, thus decreasing overall fuel consumption. An important caveat is that by allowing for more efficient use of existing capacity, congestion pricing may also allow for more total peak-hour trips. If at least some of these are new trips as opposed to trips that otherwise would have been taken using congestion pricing, however, is that it keeps traffic moving smoothly; as noted previously, this allows a facility to accom- modate much greater vehicle throughput per lane per hour than occurs when the lanes become significantly congested. Broad application of congestion pricing throughout the net- work of highways within a region could therefore allow more vehicles to use those highways during peak hours, in turn drawing off some of the traffic from parallel free routes. Incidentally, the benefit of allowing increased vehicle throughput does not necessarily apply to all forms of conges- tion pricing. Cordon congestion tolls, for example, tend to reduce total vehicle use within the priced zone. In the three major cordon toll areas implemented to date, overall traffic volume in the charge area declined by 30% in London [Trans- port for London (TfL) 2008], 22% in Stockholm (City of Stockholm 2006) and 45% in Singapore (Willoughby 2000). Improving safety outcomesâmoderately effective (uncer- tain). By promoting more even traffic flow and eliminating the abrupt stop-and-go conditions associated with traffic conges- tion, it is possible that congestion tolls could lead to improved safety outcomes, although the research team is not aware of studies to confirm this. While evidence indicates that cordon tolls can be effective in reducing vehicle crashes (TfL 2008), this is likely to be at least partly a result of reduced traffic volume. As noted previously, congestion pricing on the freeways would actually support greater overall volume during peak hours. Improving air qualityâmoderately effective (uncertain). Congestion pricing can in principle reduce emissions through two mechanisms: by smoothing traffic flow and by reducing aggregate vehicle travel. Applying congestion pricing on the freeways would accomplish the former, but the effect on total travel within a corridor across priced and unpriced routes dur- ing the course of a day is unclear. At an aggregate level, conges- tion tolls should increase the average financial cost of travel while reducing the average time cost of travel; whether this interaction will lead to more or less total travel is not certain. Turning to empirical evidence, Burt et al. (2010) reviewed data from eight examples of several different types of congestion pricing, including both trials and implementations. Data on air quality effects were available for five of the examined cases. Of these, two projects were credited with air pollutant reduc- tions estimated in the range of 8.5% to 16% (depending on the specific pollutant), one resulted in an unspecified level of reductions, one resulted in no observed effects, and one led to an increase in emissions, although the level of increase was less than that which occurred on a control roadway. Reducing GHG emissionsâmoderately effective (uncer- tain) The real-world effects of congestion pricing on GHG emissions have not been closely studied (Burt et al. 2010), but they should be broadly similar to the effects on local air pollution. In modeling the effects of congestion reduction on greenhouse gas emissions under realistic driving conditions,
240 amount to which they need to rise in order to maintain opti- mal flowâoffers a helpful measure of the disparity between demand and available capacity. Assuming that travel behavior correlates at least roughly with economic activity, the rela- tive level of congestion tolls on different facilities should help clarify where additional capacity investments would allow for the greatest productivity gains. Environment and public healthâmoderately positive (uncertain). As described above, the environmental effects in terms of local air quality and greenhouse gas emissions are likely to be moderately positive, though this is viewed as uncer- tain. Additionally, the more productive use of existing capac- ity enabled by congestion pricing may reduce the need for investment in new capacity, which could offer environmental benefits. Congestion pricing could also encourage some mode shift to non-automotive alternatives; in combination with improved air quality, this could offer benefits to public health. Equityâmoderately positive. The equity implications of congestion pricing can range from positive to negative and will generally vary from one project to another. Relevant con- siderations include how equity is defined, the type of pricing scheme to be employed (e.g., HOT lanes versus cordon tolls), and how the revenue stream is directed. In terms of possible definitions for equity, congestion pricing performs quite well with respect to aligning costs and benefitsâspecifically, those who benefit the most from faster peak-hour travel must also pay higher costs. On the other hand, congestion pricing may have negative equity effects for drivers, particularly those from lower-income or other disadvantaged groups, who find themselves priced off of the roads during peak hours. This is most problematic, however, for cordon tolls and network- wide congestion pricing, which apply to all roads in an area and offer no untolled options. It is much less of a problem for managed lanes, as envisioned in this assessment, because drivers would still have the option of using the remain- ing general-purpose lanes for free. To further address any remaining equity concerns, some of the resulting revenue can be directed to investments that tend to benefit disadvantaged groups, such as improved transit options. Additionally, it is possible to offer discounts or exemptions to lower-income drivers to lessen any negative effects (Ecola and Light 2009). Finally, it is worth noting that congestion pricing can be less regressive than other forms of taxation often used to fund transportation, such as sales taxes (Schweitzer and Taylor 2008). In short, the form of congestion pricing assumed here is likely to perform well for some measures of equity and be relatively neutral for others. K.3.5 Barriers While congestion pricing has been widely touted as an effective strategy to reduce congestion, few cities have yet other routes or at different times of day, the aggregate effect on reduced fuel use could be diminished. This creates some uncertainty for the rating. Reducing energy cost of travelâmoderately effective. From the perspective of an individual driver, as described previously, the smoother traffic flow on congestion-priced facilities would lead to greater realized fuel economy, in turn reducing the energy cost of travel. (Note, however, that the total monetary cost of driving would likely increase as a result of the tolls, but this would be offset by the value of reduced travel time and greater travel time reliability.) K.3.4 Other Effects A shift to broader application of congestion pricing would provide strong economic benefits and could offer more mod- est environmental and equity gains. Economyâhighly positive. Congestion pricing would provide strong support for greater economic efficiency and growth in at least three ways. First, from a theoretical view, congestion pricing helps to better align the cost that a driver pays for each trip with the full social cost (including delays imposed on others) imposed by the trip (Downs 2004). This leads drivers to ration their least-valued trips (i.e., those for which the benefits are exceeded by the costs, with the latter including previously unpriced congestion delays), thus lead- ing to more economically efficient use of the system. In more practical terms, failure to reflect the cost of congestion delays in the price of travel leads to overconsumption of road space, which in turn manifests as traffic congestion. Congestion pricing, in contrast, stimulates changes in travel behavior that result in significantly reduced peak-hour delays. In terms of concrete economic effects, this would lower the delivery time and cost of freight movements; it would lead to better quality of life, which could help attract companies and employees to locate in a region; and it would reduce the costs of excess fuel consumption caused by inefficient stop-and-go traffic patterns, potentially leading to marginal gains in disposable income and consumer demand. Second, as described earlier, congestion pricing would lead to significantly more productive use, in terms of vehicles per lane per hour, of existing highway capacity, thereby reducing the level of public investment needed to provide a given level of service. Third, congestion pricing would create a potentially sig- nificant revenue source to fund needed transportation invest- ments. And, unlike other revenue mechanisms, congestion tolls would provide unambiguous information about where to direct investments in order to provide the greatest eco- nomic benefits (NSTIFC 2009). Specifically, when congestion tolls are structured to vary with demand in order to maintain smoothly flowing travel, the level of the tollsâthat is, the
241 revenue sources such as fuel taxes and registration fees, many toll roads are operated by private industry. If a state were to pursue broad application of congestion tolls, it might choose to engage one or more private firms to assist in setting up and operating the system. Developing the capacity to work with industry in this manner could, for some states, require moderate institutional restructuring. Additionally, if local jurisdictions within a state decided to set up cordon tolls or network-wide congestion pricing on the arterials to be integrated with state-levied congestion tolls on the freeway system, it would be necessary to set up a collaborative insti- tutional partnership between the state and local jurisdictions to allow for proper collection and distribution of revenue. K.3.6 Required Lead Time Although electronic tolling technology is already proven, setting up a congestion tolling network covering all congested freeways would still be somewhat complex and time consum- ing. If expedited, however, it could plausibly be accomplished within a 5-year time frame once the decision to do so had been made. K.3.7 Qualifications Congestion pricing is appropriate for congested areas, which for the most part means metropolitan areas. Thus this strategy will be most applicable for states that have large urban areas and less applicable for predominantly rural states. K.4 Intelligent Transportation Systems The term âintelligent transportation systemâ describes the use of advanced applications involving vehicle-to-vehicle (V-V) and vehicle-to-infrastructure (V-I) communications to improve safety, mobility, and operating efficiency in the trans- portation network. The U.S. Department of Transportationâs ITS Joint Program Office describes its mission as focusing on âintelligent vehicles, intelligent infrastructure and the creation of an intelligent transportation system through integration with and between these two components.â The Connected Vehicle initiative, formerly called IntelliDrive or vehicle-infrastructure integration (VII), includes the development of safety, mobility, and environmental applications that use real-time and archived data to improve vehicle operation and reduce crashes, improve transportation system management and operations capabili- ties, and reduce the environmental impacts of travel-related choices (RITA 2012b). There is considerable overlap, in terms of applicable technologies and objectives, between ITSs, as defined previ- ously, and rapidly emerging autonomous vehicle technology. turned to congestion pricing as a solution. This stems from the considerable barriers that confront congestion tolls. Low public supportâsignificant barrier. Similar to direct user fees, the adoption of congestion pricing is hampered by lack of public support and in some cases active opposition. This low support can be attributed to a lack of understanding regard- ing fuel taxes (many drivers have little idea about how much they currently pay in fuel taxes) and a corresponding view that congestion tolls would represent double taxation, opposition to increased taxes and fees in any form, concern that the sup- porting technologies will lead to further erosion of privacy, concern that lower-income drivers will be further disadvan- taged, and skepticism that congestion pricing will achieve its goals. Political leaders are generally sympathetic to such con- cerns. Also, the current lack of public experience with pricing appears to make a difference. With regard to cordon pricing in Stockholm and London, opinion polls found that public sup- port increased once the systems were put in place and proved to be effective. In Stockholm, support increased from about 30% to just over 50% (Algers, undated), while in London, sup- port rose from 40% to 57% (Glaister 2007). Different forms of congestion pricing have ranged widely in their level of public support in the United States, with general approval of HOT lanes in most locations and active opposition to cordon pric- ing in New York City. Given that the approach considered here would involve the conversion of general-purpose lanes to priced lanes, it seems safe to assume that low public support would likely prove a significant barrier. Technical riskâmoderate barrier (uncertain). While well- developed technologies for collection of congestion tolls exist, there still may be some risk. For example, a state might choose to implement congestion pricing on all congested freeways as part of a larger shift to mileage-based user fees. This would likely entail the deployment of a more complex system archi- tecture, introducing some technical uncertainty. Enabling legislationâsignificant barrier. Broader applica- tion of tolling on congested freeways would almost certainly require enabling state legislation. While the most comprehen- sive appraisal of legal issues at the state level was done with regard to mileage-based user fees, the findings from that review suggest that legislation would be helpful and in some cases necessary in dealing with such issues as whether the charges are legally viewed as taxes, fees, or tolls; whether there are limits on how revenues can be used; how rates would be set; how revenues would be collected and distributed; whether operations could be outsourced; how violations would be enforced; and how to ensure driver privacy (I-95 Corridor Coalition 2010). Enabling federal legislation would also likely be needed before states could pursue this strategy for general- purpose lanes on Interstate highways. Institutional restructuringâmoderate barrier (uncer- tain). In contrast to other common state transportation
242 ing weather events, to smooth vehicle flows during periods of roadway congestion and prevent shockwaves that reduce vehicle throughput or cause rear-end collisions, and to opti- mize aggregate fuel consumption and emissions based on environmental factors (RITA 2012b). V-I applications are already being used to more efficiently weigh and screen commercial vehicles and cargo and help commercial vehicle drivers find safe places to park and rest. Positive train con- trol, a form of V-I integration for trains, is being used today to keep trains at safe operating speeds and at safe distances. Bus rapid transit signal prioritization, in which an electronic message transmitted from an oncoming bus instructs a traf- fic signal to turn green a little earlier or remain green a little longer, is another current example of V-I communication applications. Other ITS and connected-vehicle policies. Aggregations of vehicle travel data compiled from V-V and V-I applications can be used by transportation system operators to improve system operating efficiency, or they can serve as the basis for real-time traffic information across the road network that allows travelers to adjust their trip decisions accordingly. Both of these are described in the subsequent TSM&O strat- egy assessment. As noted, there is a close relationship between ITSs and TSM&O. Assumed policies for assessing ITSs and connected vehicles. ITSs and connected-vehicle systems are still being developed, deployed, and improved on. The following assess- ment of this strategic direction assumes that a state would take an active roleâfor example, upgrading infrastructure with appropriate sensing technologyâin support of the even- tual implementation of ITSs in which many real-time vehicle operating decisions are automated or heavily assisted by onboard computers. K.4.2 Intended Mitigation Effects Core policy aims of ITSs include reducing traffic conges- tion and improving safety outcomes. Additionally, adoption of an ITS could offer air quality and GHG emission reduction benefits. Reducing traffic congestionâmoderately effective. At full implementation, an ITS could help optimize flows and reduce system-wide traffic congestion by rerouting vehicles, passengers, and freight around bottlenecks and incidents. Also, by maintaining appropriate headways between vehicles, ITSs could reduce the need for sudden braking that can trig- ger stop-and-go traffic conditions. Likewise, ITSs could pre- vent a significant percentage of vehicle crashes, one of the major sources of nonrecurrent traffic congestion. However, while an ITS can make more efficient use of existing capacity, it would do little to halt any growth in travel demand that might result from other factors (e.g., economic and popu- The latter, however, requires much less in the way of pub- lic investmentâthough it would still require federal or state action to establish relevant legal and regulatory frameworksâ and in particular does not depend on V-I communications to support much of the intended functionality. Thus, autonomous vehicles could prove successful even if the gov- ernment does not choose to invest in instrumenting the road network with sensors and electronic communications tech- nologies. This creates some degree of risk that major public investments in ITSs could be overtaken and rendered super- fluous by private-sector development of autonomous vehicles. There is also some overlap between ITSs and the strategy of focusing on improved TSM&O, discussed later in this appen- dix, as both rely on technology to improve the transporta- tion system. The key distinction being made in differentiating between these two strategies is that ITSs, despite their con- siderable promise, are still emerging and for the most part remain unproven in terms of broadscale application; thus, both the cost and technical risk factors are significant. In con- trast, TSM&O involves proven technologiesâsuch as free- way ramp metering or traffic signal synchronizationâthat are already widely used but in some cases could be upgraded or deployed to additional areas. K.4.1 Supportive Policies ITSs and connected vehicles strategies are commonly dis- cussed in two areas: V-V applications and V-I applications. V-V applications. By providing drivers and automated vehicle control systems with information on external condi- tionsâsuch as the relative location of other vehiclesâsuch connected-vehicle applications can identify hazards and take steps to avoid crashes or loss of vehicle control. V-V applica- tions such as proximity warnings and advance notification of rapid deceleration by downstream vehicles allow drivers to assess threats and react more quickly. Increasingly, V-V appli- cations are interacting with automated on-vehicle safety sys- tems like adaptive cruise control that maintain a safe distance between two vehicles with no need for driver input. Transit V-V applications include the ability for drivers to determine when bus headways are reaching unacceptable levels due to bunching or spreading, or when a bus or train should wait at a stop to facilitate passenger transfers. Currently, these appli- cations are limited to newer vehicles and are not fully inte- grated systems. In the future, these technologies could allow for roadways to accommodate significantly more vehicles traveling in very close proximity and at extremely high speeds with virtually no driver instructions (RITA 2012b). V-I applications. Wireless communications technologies have greatly simplified and reduced the costs associated with V-I applications. Emerging technologies include the ability to control vehicle speeds and maintain safe operations dur-
243 K.4.4 Other Effects From a broader perspective, the effects of ITSs should be positive for both the economy and the environment, and neutral with respect to equity concerns. Economyâhighly positive. ITS technologies should increase effective system capacity, safety, and the cost of travel in comparison to current conditions. By moving more pas- sengers and freight per lane mile or track mile, an ITS would help the system operate more efficiently, in turn providing net positive economic benefits at both the micro and macro scales. Additionally, an ITS would dramatically reduce the number of crashes and their attendant economic costs. Environment and public healthâmoderately positive. As discussed earlier, the effects of ITSs on air quality and greenhouse gas emissions, although uncertain, are expected to be positive. Additionally, ITSs would reduce the need for system capacity expansion and its associated environmental costs. The potential effects of ITS investments in improving air quality, improving safety, and enhancing non-automotive travel modes should all be beneficial for public health. Equityâneutral (uncertain). ITS applications that improve transit service should have positive equity effects, given that transit is most frequently used by lower-income households and other disadvantaged groups. The same technology, though, can make vehicle travel even more attractive. Due to the high costs of incorporating ITS technology into private vehicles, there could be an initial period during which many of the ITS benefits would accrue mainly to wealthier drivers with newer vehicles, as well as to commercial vehicles. Over time, though, as the technology diffused through the passenger fleet, the ben- efits would be more widely shared. Taking these various factors into consideration, the equity effects appear to be neutral, if somewhat uncertain. K.4.5 Barriers There are a number of barriers to implementing full-scale ITSs, and most of these are likely to be significant. Low public supportâmoderate barrier. The public is often resistant to major shifts in technology, and this could prove to be the case with ITSs. One possible concern relates to driver privacy. Additionally, there could be resistance to the notion that ITSs would give greater control to either the government or to computer systems over vehicle operations, route selection, and the like. Financial costâsignificant barrier. Developing advanced ITSs would be an expensive proposition, involving the inclusion of enabling technology within each vehicle, the retrofitting of existing infrastructure with sensors and com- munication capabilities, and the development of computing and telecommunications platforms to integrate the overall system. While the investment would likely be repaid over time lation growth). To fully mitigate traffic, therefore, it would likely be necessary to pair an ITS with complementary supply and demand policies such as congestion pricing, transporta- tion demand management, and strategic capacity expansion, where appropriate. Improving safety outcomesâhighly effective. Safety is one of the primary benefits expected from ITS applica- tions. Connected-vehicle safety applications offer the promise of eliminating up to 82% of crash scenarios with unimpaired drivers, preventing tens of thousands of automobile crashes every year (RITA 2012b). Improving air qualityâmoderately effective (uncertain). With the reductions in stop-and-start traffic conditions pos- sible with ITS applications, local and regional air quality may be positively affected. However, air quality improvements will depend on the current fuel and fleet mix in use and may be offset by additional induced or latent travel demand increases as a result of system optimization. Improving GHG emission reductionsâmoderately effec- tive (uncertain). Similar to air quality improvements, smoother traffic flow conditions should translate to improved fuel economy, thereby reducing GHG emissions per vehicle mile. Increased vehicle travel spurred in part by improved system effi- ciency could, however, offset such benefits. Enhancing non-automotive travel optionsâmoderately effective. Any benefits in reducing traffic congestion would accrue to bus transit as well, and the ability of transit vehicles to communicate with traffic signals for bus signal prioritization would also speed bus journeys. K.4.3 Intended Shaping Effects Although ITSs are not primarily aimed at energy technolo- gies, successful deployment could help reduce fuel consump- tion and, in turn, the cost of travel. Reducing oil consumptionâmoderately effective (uncer- tain). For most vehicles, fuel economy is greatest at between 40 and 60 miles per hour (Barth and Boriboonsomsin 2007). I-V applications can control vehicle speeds to optimize fuel efficiency depending on roadway conditions. Vehicle control technologies that reduce speeding, rapid acceleration, and hard braking can improve individual vehicle gas mileage by 33% at highway speeds. The use of cruise control can improve vehicle fuel economy by up to 7% (I-95 Corridor Coalition 2011). Yet while individual vehicle fuel economy may be improved, full-scale ITS implementation would also increase the effective capacity of the road network, potentially induc- ing more total travel. Thus the rating is qualified as uncertain. Reducing energy cost of travelâmoderately effective. From the perspective of the individual driver, as described previously, ITSs would enable greater fuel economy, in turn lowering the energy cost of travel.
244 K.5 Transportation Systems Management and Operations TSM&O encompasses systems, services, and projectsâ potentially multimodal and cross-jurisdictionalâinvolving the collection, analysis, and application of real-time and archived system performance data to actively manage trans- portation infrastructure and services. TSM&O applications seek to make more efficient use of existing capacity and to improve the security, safety, and reliability of transportation systems (FHWA 2008b). In its focus on the application of data integration and sophisticated analytics to improve trans- portation systems, TSM&O can be viewed as similar to ITSs, described earlier in this appendix. The term âITS,â however, is often used to describe advanced applications, such as high- speed vehicle platooning, that may not be deployed for many years. In contrast, TSM&O focuses on well-defined applica- tions of existing technologies that are already deployed in the active management and operations of transportation systems. K.5.1 Supportive Policies Many TSM&O applications are already commonly used by DOTs. This assessment focuses on core approaches to system management and operations, including multimodal applica- tions, as well as on real-time system information and incident management practices. Proactive traffic management. Historically, many states first initiated TSM&O programs with a focus on better man- agement of freeway and arterial traffic. Early applications were signal synchronization, ramp metering, and variable speed limits. The underlying technology has advanced considerably in recent years such that further benefits can often be achieved by upgrading older systems. Adaptive signal control systems, for example, are now able to respond to real-time traffic con- ditions by adjusting phase and cycle lengths to accommodate uneven flows of traffic through intersections in a corridor or network. Some signal control system algorithms can com- bine real-time and archived data to proactively adjust signal times to prevent or significantly reduce intersection-related bottlenecks, particularly during recurring special events or holiday weekends. Ramp metering evenly distributes traffic merging onto a congested freeway. Variable speed limits, or speed harmonization, help prevent disruptive shockwaves from forming in a stream of traffic that is nearing the lim- its of the roadwayâs capacity. Hard shoulder running, or the allowable use of roadway shoulders, during peak travel times, may be communicated by variable message signs. Multimodal system management. Transit agencies use automatic vehicle location (AVL) and global positioning systems (GPSs) to track locations of buses to better manage on-time performance, bus headways, and the synchroniza- tion of arrivals and departures at intersecting transit routes. The net effect is to improve efficiency and reduce average through greater operational efficiencies, it could still prove challenging to assemble the necessary up-front investment. Technical riskâsignificant barrier. ITS technologies face significant technical risks and will require extensive test- ing before they can be approved for use by federal or state governments and accepted by regulatory agencies, insurers, vehicle owners, and fleet operators. Of particular concern, for example, is the possibility that bugs in a system involving semi-automated vehicle control could lead to fatal crashes. Such systems would need to be proven as highly reliable prior to deployment, and the prospects for success in this regard are not certain. From the perspective of a state interested in an ITS, then, there is a real risk that early investment in an ITSâfor example, equipping roads with sensors and tran- sponders in anticipation of ITS-equipped vehiclesâwould not ultimately lead to successful implementation and thus would represent wasted resources. Also, as discussed earlier, it is quite possible that rapidly emerging autonomous vehicle technology could provide many of the promised benefits of an ITS with little in the way of public investment. This com- pounds the risk that significant state investments in an ITS would yield little additional benefits. Enabling legislationâsignificant barrier (uncertain). Broad application of ITSs would likely require legislation to clarify privacy, liability, and data ownership issues, possibly at the federal level. For example, it might be necessary to specify which parties could be held liable in a crash involving one or more vehicles equipped with semi-automated collision- avoidance systems. ITSs might also provide access to much more detailed information about individual travel behavior, motivating legislation to clarify privacy rights in the context of telematics. Institutional restructuringâsignificant barrier. ITSs could affect who is responsible for operating and maintaining which components of the transportation systemâincluding, poten- tially, a larger role for private-sector systems integrators. In order for the system to be fully optimized, either a central authority or strong institutional and cross-jurisdictional coordination mechanisms will need to be in place. Given the complexity of implementing ITS technologies to date in many metropolitan areas, institutional barriers could represent the most significant obstacle to overcome in implementing these strategies. K.4.6 Required Lead Time Given the span of challenges, full implementation of ITSs and connected-vehicle systems would likely require greater than 20 years of lead time. K.4.7 Qualifications ITSs should be applicable in all states, although the specific applications most helpful could differ between rural travel conditions and urban travel conditions.
245 special event traffic more quicklyâcan help mitigate these challenges. Emergency medical services, fire, police, and tow operators are all key partners with transportation agencies in implementing incident management strategies. Many traf- fic management centers invite emergency responders to sta- tion personnel at the center to facilitate communication of information about the location and severity of incidents (for example, via a live video feed or closed-circuit transmission of audio from first responders). Roving road-service patrols and pre-positioning of emergency responders and equip- ment can cut incident response and clearance times, helping to relieve incident-related bottlenecks and safety hazards. Assumed policies for assessing TSM&O. In assessing the potential effects of TSM&O, it is assumed that a state DOT would invest aggressively in the applications described previ- ously as appropriate, particularly in larger metropolitan areas most prone to traffic congestion. In some cases this could involve upgrading to latest-generation technology, such as with ramp metering, while in other cases it might involve deploying technology for the first time. It is further assumed that the state DOT would work with local agencies and tran- sit operators to implement multimodal, cross-jurisdictional applications such as integrated corridor management. K.5.2 Intended Mitigation Effects Core motivations for TSM&O applications include reduc- ing traffic congestion, improving safety, and, in some cases, improving the quality and efficiency of transit services. Addi- tionally, deployment of TSM&O strategies can help improve air quality and reduce greenhouse gas emissions. Reducing traffic congestionâmoderately effective. One of the primary motivations of TSM&O policies is to relieve traf- fic congestion and associated impacts, and available evidence indicates considerable success in this regard. According to FHWA (2004), full deployment of TSM&O policies can reduce delay in congested urban areas by as much as 15%. Research on the impacts of ramp metering, signal coordination, arte- rial access management, and incident management strategies in metropolitan areas shows reductions in traffic delays of up to 40% (Schrank and Lomax 2010). The main limitation of TSM&O policies with respect to reducing traffic is that over the longer term, the effects of latent and induced demand may lead to more total peak-hour travel, offsetting some of the initial improvements. Improving safety outcomesâmoderately effective. Inci- dent management approaches, a core component of TSM&O, help remove obstacles and bottlenecks, reduce rear-end col- lisions that occur in stop-and-go traffic, and lower the rate of secondary crashes at incident scenes. Variable speed lim- its, peak-period shoulder use, and ramp metering have been shown to reduce both the likelihood and severity of conflicts and have an overall positive effect on safety (Waller et al. 2011). passenger wait times. Positive train control (PTC) technol- ogy allows train dispatchers to monitor train locations and control speeds to prevent collisions between trains, reduce the likelihood of incidents involving construction work- ers and equipment, and reduce derailments due to excess speeds. Increasingly, integrated corridor management (ICM) approaches are allowing for more sophisticated manage- ment of multiple parallel roadways and transit facilities in a single corridor. Freeway system management, arterial signal systems, bus operations, and rail operations can be managed jointly by implementing a complementary set of strategies across modes. ICM requires sharing of information across jurisdictional boundaries and institutional silos and allows more comprehensive information to be disseminated to sys- tem users (RITA 2012a). Real-time system information. Providing up-to-date infor- mation about travel times, incidents, delays, weather-related closures, and congestion on multiple modes and routes helps transportation system users decide whether to make a trip, when to start a trip, what mode to use, and what route to take. Real-time system information can be delivered via on-road variable message signs (such as those that display travel times to downstream destinations, sometimes via two alternative routes), via audio and video systems in transit stations and on transit vehicles (including screens or public address announce- ments with next-vehicle arrival times and information about delays and service disruptions), to wireless communication devices (including navigation devices, smartphones, and tab- lets), via public and private websites, via toll-free phone num- bers such as 511 systems, via dedicated short-range highway advisory radio, and via broadcast media (traffic and transit updates on the radio and television news). Real-time system information is also sometimes monitored by a central dis- patcher employed by a truck or bus fleet operator and then relayed to drivers by radio (Deeter 2009). As discussed in the earlier assessment of the ITS strategy, one of the potential benefits of the U.S. Department of Transportationâs Con- nected Vehicle research initiative is to expand real-time data availability to include information on situational safety risks, environmental and weather conditions, congestion data, real- time cost information (for example, variable toll rates on man- aged lanes), and parking availability (both at truck rest areas and in urban parking garages). Future real-time data and computational algorithms could also allow for comparisons of costs and travel times via multiple modes (RITA 2010). Incident and delay management. Incident management is another area in which TSM&O approaches can offer sig- nificant benefits. Weather, natural disasters, crashes, special events, and construction work zones can all lead to additional, and in some cases unpredictable, traffic delays and safety risks, and the application of certain TSM&O technologiesâ for example, warning of downstream incidents or roadwork on variable message signs or altering signal timing to clear
246 previously, is to reduce traffic delays. Given that vehicle fuel economy is much lower in heavily congested stop-and-go traffic conditions (Barth and Boriboonsomsin 2007), reduc- ing traffic congestion has the effect of increasing average fuel economy during actual driving conditions, in turn driving down total oil consumption. Yet, as a result of latent demand, improving travel conditions can often serve to encourage more drivers to use the roads during peak hours, undercut- ting some of the traffic reduction benefits and adding more fuel consumption. Although there still may be some overall reduction in fuel use, the degree to which these factors offset one another is unclear. Reducing the energy cost of travelâmoderately effec- tive. From the perspective of an individual driver, greater fuel economy resulting from reduced traffic delays translates directly to a lower average energy cost per mile of travel. K.5.4 Other Effects Pursuing TSM&O strategies could lead to modest, if sec- ondary, benefits with respect to the economy and environ- ment, and should be neutral with respect to equity. Economyâmoderately positive. TSM&O approaches can be expected to offer a range of benefits for transportation system users, including reduced delays, improved travel time reliability, reduced vehicle fuel costs, and improved safety conditions. These benefits can be quantified in economic terms and should be positive for individual travelers, busi- nesses, and the economic productivity of a region as a whole. Environment and public healthâmoderately positive (uncertain). By reducing congestion delays, TSM&O strategies can help improve vehicle fuel economy and reduce emissions. They should help reduce crashes, with positive implications for public health. By providing better information about alter- native modes of travel, they can also lead to increased transit ridership. Over the longer term, TSM&O applications may support additional vehicle travel stemming from latent and induced demand, and this could undermine some of the envi- ronmental and public health benefits. On balance, though, the net effects are likely to be positive, if uncertain. Equityâneutral. TSM&O approaches can improve travel conditions for both drivers and transit users, resulting in an overall rating of neutral. It is also worth noting that TSM&O applications can defer the need for other congestion-reduction strategiesâsuch as building new capacityâthat may pose greater equity concerns. K.5.5 Barriers While full implementation of TSM&O poses some barriers, most are moderate in nature. This stems from the fact that TSM&O technologies are already proven and widely deployed. Improving air qualityâmoderately effective (uncertain). By reducing stop-and-go travel conditions, TSM&O appli- cations can yield reductions in the emissions of harmful air pollutants. For example, in a study that examined the retiming of 640 traffic signals in Michigan, the results indicated that carbon monoxide emissions were reduced by 2.5%, nitrogen oxide emissions were reduced by 3.5%, and hydro carbon emissions were reduced by 4.2% (RITA 2011). Over the longer-term, however, such benefits may be at least partially undermined if improved traffic flow leads, as a result of latent demand, to additional vehicle travel. Thus the rating is quali- fied as being uncertain. Reducing GHG emissionsâmoderately effective (uncer- tain). Through reducing traffic congestion and promot- ing smoother traffic flow, TSM&O strategies may reduce the average amount of fuel consumed and, in turn, GHG emis- sions, per passenger mile. The main uncertainty is whether the reduction in congestion will lead to greater total travel, potentially offsetting these benefits. Enhancing non-automotive travel optionsâmoderately effective. A core benefit of TSM&O is to reduce congestion delays, and this would assist in improving bus transit times as well. Some TSM&O applications, such as traffic signal priori- tization for bus rapid transit, focus specifically on improving transit options. Traveler information systems can also pro- vide more and better information about multimodal options, assisting in the initial trip planning process as well as providing up-to-date information on vehicle arrivals and departures dur- ing the course of travel. Evidence indicates that such improve- ments often translate into gains in ridership. In the United Kingdom, the introduction of real-time transit information in combination with increased marketing led to gains in tran- sit use that translated into a reduction in automotive travel of between 2% and 6% (Jones 2003). According to Tang and Thakuriah (2012), popular smart-phone applications to access information on transit routes and timing have been shown to have modest positive impacts on bus ridership in urban areas. Results from TCRP Report 118: Bus Rapid Transit Practitionerâs Guide indicate that comprehensive bus rapid transit programs, which rest in part on TSM&O applications, can increase rider- ship from 35 to 75% (Kittelson and Associates, Herbert S. Levinson Transportation Associates, and DMJM+Harris 2007). K.5.3 Intended Shaping Effects While TSM&O strategies are not principally intended to influence energy use patterns, they could have a modest effect on improving fuel economy through improved traffic flow, thus reducing oil consumption and decreasing the energy cost of travel. Reducing oil consumptionâmoderately effective (uncer- tain). One of the main benefits of TSM&O, as described
247 Statistics and Analysis 2010). Highway safety improvements over the past 50 years of have focused largely on crash sur- vival, while the current focus has shifted to the prevention of crashes. Over the next several decades, changes in the marginal cost of driving associated with alternate fuels and vehicle technologies could have the effect of increasing aggre- gate traffic volumes and congestion levels. Additionally, it is possible that consumers could opt for smaller passenger cars, whereas the goods movement industry could shift to larger truck configurations for greater efficiency, heightening the risks associated with vehicleâtruck collisions. Absent addi- tional safety interventions, such shifts could boost the overall number of crashes, fatalities, and injuries that occur on the nationâs roadways each year (Pisarski and Council 2010). K.6.1 Supportive Policies This assessment focuses on three groupings of related poli- cies and actionsâmeasures to reduce roadway departures, intersection improvements, and pedestrian and cycling improvementsâthat could enable states, through increased levels of investment, to further reduce crashes, fatalities, and injuries. Several other approaches to safety are briefly men- tioned but not fully discussed in this assessment. Roadway departure reduction measures. More than half of all vehicle crash fatalities result from roadway departures, which are frequently severe in nature. Strategies to reduce road departures generally involve roadway design improvements, including rumble strips, skid-resistant pavements, median barriers, and modifications to highway alignments, curves, and shoulders. Many of these measures have been shown to be cost-effective, yielding substantial risk reductions. Centerline rumble strips have been documented to result in a 44% reduction in head-on fatal crashes on rural two-lane roads and a 64% reduction on urban two-lane roads (Torbic et al. 2009). Flattening side slopes, removing guardrails, and flattening crests on vertical curves can reduce crashes by 50% to 80%, depending on roadway type (Hovey and Chowdhury 2005). Intersection improvements. Vehicle crashes at dangerous intersections are the second leading cause of highway fatalities. Key strategies to improve intersection safety include design and operational changes that increase visibility, decrease turn- ing movements, minimize access conflicts, maximize traffic intervals, or add traffic control signals and warning devices. Traffic engineers may consider a wide variety of intersection improvements, ranging from subtle changes in signal timing or all-red light clearance times to major improvements such as roundabout installations or access management changes. Increasingly, states are applying systematic methods of identi- fying dangerous intersections and determining the most cost- effective improvement projects. Changes in crash frequency and Financial costâmoderate barrier. TSM&O applications offer a less-expensive systematic approach to mitigating traf- fic congestion and other concerns. Still, deploying the neces- sary technology is not inexpensive and requires considerable up-front costs. To deploy the types of applications included in TSM&O on a broad scale, many states might find it neces- sary to first increase available funding streams. Technical riskâmoderate barrier. Most TSM&O appli- cations rely heavily on technology that may require custom integration within a particular context, thus posing some technical risk. Technologies that are poorly implemented or improperly applied could actually worsen congestion and create safety issues that did not previously exist. Enabling legislationâmoderate barrier. Provision of real-time system information may rely on data gathered from system users with or without their explicit permission. Due to privacy concerns, some states have made it difficult to col- lect and distribute such information to private-sector partici- pants, who often have a role in processing and disseminating real-time system information. Institutional restructuringâmoderate barrier. Effective design and implementation of TSM&O programs, such as for signal timing, may require the collaboration of state and regional transportation agencies, local inter-governmental cooperation, and coordination among public- and private- sector partners. There are examples of effective institutional coordination arrangements for the implementation of TSM&O strategies. K.5.6 Required Lead Time The majority of TSM&O strategies, depending on com- plexity, can be implemented in a 1- to 5-year time frame. K.5.7 Qualifications TSM&O strategies may be implemented in any context, but benefits are greatest in metropolitan regions that expe- rience high congestion as a routine matter. In rural areas, TSM&O strategies often are targeted to congestion during recurring special events and nonrecurring emergency events, or to managing peak intercity traffic levels during holiday weekends. K.6 Improving Traffic Safety Federal guidelines, state priorities, and auto manufacturer emphasis on improving roadway, driver, and vehicle safety have helped reduce the national rates of crash-related inju- ries and fatalities to their lowest recorded level. Still, more than 30,000 persons die in motor vehicle crashes each year, and many more are injured (NHTSA, National Center for
248 greater traffic safety by increasing the level and pace of invest- ments in projects aimed at reducing crashes from roadway departures, collisions at intersections, and collisions involv- ing pedestrians and cyclists. Depending on the state, and rec- ognizing the need to allocate scarce resources to address a broader spectrum of DOT activities, increased investment in safety projects could require a state to augment transporta- tion revenue. A state pursuing this strategy would logically address the most dangerous facilities, intersections, and grade crossings first, leading to substantial initial improvements in safety. Over time, additional safety investments could yield lower benefits at the margin, but it is assumed that a state would continue to invest in safety projects for which the ben- efits appear to exceed the costs. K.6.2 Intended Mitigation Effects The main intent of this strategy would be to reduce crashes, including crashes involving bicyclists or pedestrians, and crash-related fatalities and injuries. As positive by-products, this strategy could also help reduce traffic congestion and improve non-automotive modes of travel. Reducing traffic congestionâmoderately effective. Traf- fic incidents can be responsible for a significant share of non- recurrent traffic congestion in urban areas (Downs 2004). By helping to reduce the number of crashes, this strategy should also help reduce nonrecurrent traffic delays. Improving safety outcomesâhighly effective. Highway safety improvements are well researched and documented. Advances in design, operations, and technologies continue to contribute to the improved effectiveness of safety interven- tions and countermeasures. The FHWAâs Office of Safety and NHTSA, in cooperation with other federal and state agencies, industry associations, and private contractors, have produced a wealth of information to help states incorporate the most effective and proven safety improvements into new projects and to redesign and retrofit existing problem areas. The Crash Modification Factors Clearinghouse provides a database of researched crash-reduction probabilities and factors for use by traffic engineers (FHWA, undated). The documented effectiveness of safety improvements ranges from negative (in the case of bike lanes, which tend to increase the number of cyclists and in turn the number of cyclist-involved crashes) to marginally effective (in the case of small changes to signals at intersections or road signs) to very effective (in the case of roadway redesign or pedestrian projects). A coordinated and fully implemented safety improvement program across a state could be considered highly effective at continuing to reduce the incidence and severity of vehicle crashes. Enhancing non-automotive travel optionsâmoderately effective. Making walking and cycling safer through pedes- trian crossings or overpasses, for example, will enhance the severity vary considerably with the type of improvement and characteristics of the roadway, but expected safety improve- ments can be considerable. For example, replacing inter- sections with roundabouts on high-speed rural roadways can reduce crash frequency by 84% (Isebrands 2009.) Add- ing left-turn lanes to major road approaches at urban inter- sections can reduce crashes by 47% (Harwood et al. 2003). Pedestrian and cyclist protections. The majority of pedestrian and cyclist conflicts with motor vehicles occur in urban areas and most often in non-intersection areas of the roadway (NHTSA 2012). Many cities with high rates of cycling and walking are redesigning urban areas to more safely accommodate nonmotorized traffic, including by embracing complete-street or pedestrian-oriented design principles. Dangerous areas with high vehicleâpedestrian crash rates are often localizedâan outdoor mall, a central business district, or school zone, for exampleâand the dangers here may be addressed with targeted safety improvements such as illumi- nated crosswalks, pedestrian overpasses, and pedestrian-only zones. Raised median refuge areas have been shown to reduce vehicle crashes with pedestrians by 46% at marked crosswalks and by 39% at unmarked crosswalks (FHWA 2012a). Other protections, which may be larger in scale, include enhanc- ing trail networks, adding bike lanes on major commute corridors, and implementing speed limit changes. Because the installation of bike lanes tends to increase the number of cyclists and thus the number of crashes, bicycle boule- vards on less-congested parallel routes are being considered as safer alternatives for urban commuters (Minikel 2011). Other traffic safety policies. Several other approaches to improving traffic safetyâincluding improved vehicle tech- nologies, ITSs, and programs to reduce distracted driving or driving under the influenceâare also worthy, but are not part of this assessment. Many auto manufacturers already devote significant effort to vehicle designs, materials, and technolo- gies aimed at helping to avoid crashes in the first place or reducing adverse consequences when crashes do occur. Exam- ples are blind spot and hazard warnings, automated braking and traction control systems, improvements in airbag tech- nologies, and the use of advanced materials. Such advances, though, are generally regulated at the federal level rather than by states, and thus are not further discussed here. ITSs, which involve vehicle-to-vehicle or vehicle-to-infrastructure com- munications to help improve the safety and efficiency of vehi- cle travel, are discussed as a separate strategy earlier in this appendix. Finally, programs to reduce distracted or impaired driving are also very important for safety, but most states are already fully engaged in such efforts. Assumed policies for assessing DOT involvement in highway safety. Safety is already a top priority in federal and state planning efforts. In assessing this strategic direction, it is assumed that a state would accelerate its progress toward
249 If safety improvements are pursued in a strategic manner that focuses on problem areas rather than on projects or in communities that can afford to install enhancements, overall equity may improve moderately. K.6.5 Barriers The main barrier to more aggressive pursuit of the safety measures discussed as part of this strategy relates to finan- cial cost. Financial costâmoderate barrier. While the safety improve- ments included in this strategy are generally recognized as being cost-effective, they can also be costly to implement. Assuming that states continue to face mounting cost constraints in the coming years, the inclusion of desired safety enhancements and improvements in highway projects could become more chal- lenging. As noted earlier, augmenting current revenue sources may therefore prove necessary. K.6.6 Required Lead Time Many roadway design and operational safety improvements require relatively little lead time and can be incorporated into new projects immediately, taking advantage of available technologies and methods. Most of the safety improvements discussed here could be achieved within a time frame of 1 to 5 years, or within the current project planning, engineering, and construction time frame. K.6.7 Qualifications This strategy direction is applicable to both populous states and less-populated, urban, and rural areas, and to most roadway and facility types. References Alameda Corridor Transportation Authority. 2012. Alameda Corridor Fact Sheet. http://www.acta.org/projects/projects_completed_ alameda_factsheet.asp (accessed January 20, 2012). Algers, S. Undated. âThe Stockholm Congestion Charging Trial.â Pre- sented at WSP Analysis & Strategy, Royal Institute of Technology, Stockholm. Arnold, R., V. C. Smith, J. Q. Doan, R. N. Barry, J. L. Blakesley, P. T. DeCorla-Souza, M. F. Muriello, G. N. Murthy, P. K. Rubstello, and N. A. Thompson. 2010 (December). Reducing Congestion and Fund- ing Transportation Using Road Pricing In Europe and Singapore. Inter- national Technology Scanning Program, Federal Highway Adminis- tration, American Association of State Highway and Transportation Officials, and National Cooperative Highway Research Program. ARTBA. 2012. FAQs: How Much Does It Cost to Build a Mile of Road. http://www.artba.org/about/faqs-transportation-general-public/ faqs/#20 (accessed April 3, 2012). Barth, M. and K. Boriboonsomsin. 2007. âTraffic Congestion and Greenhouse Gases.â Access, 35: 2â9. general quality and attractiveness of these non-automotive modes. K.6.3 Intended Shaping Effects The policies considered here would not be intended or expected to exert a major shaping influence on oil consump- tion, the use of alternative fuels, or the energy cost of travel. K.6.4 Other Effects Improvements in traffic safety could offer strong benefits for the economy along with the environment and public health. The effects on equity are less clear, though likely to be positive. Economyâhighly positive. Vehicle crash fatalities and inju- ries account for a significant economic loss to society, includ- ing the cost of death or injury to persons; the cost of property damage; the direct costs of emergency response, medical, legal, and insurance services; and significant productivity, traffic delay, and travel time reliability losses. A study sponsored by the American Automobile Association (AAA) estimated the overall social cost of vehicle crash fatalities and injuries in 99 urbanized areas across the nation to be at $299.5 bil- lion in 2009 (Cambridge Systematics 2011). The Centers for Disease Control and Prevention estimated that the direct cost of medical care associated with motor-vehicle injuries exceeds $17 billion annually (Naumann et al. 2010). Reduc- ing the frequency and severity of crashes will reduce social welfare losses, result in productivity gains for workers and the economy, and save the lives of tens of thousands of individu- als each year. Environment and public healthâhighly positive. First and foremost, safety measures will reduce crash-related fatal- ities and injuries, which will be a strong public health benefit. Policies that support walking and biking in urban and rural areas also provide environmental and public health benefits resulting from reductions in motor vehicle use and increased physical activity. Safety improvements in roadway design or intersection operations can sometimes result in lower vehicle speeds with more frequent stops (e.g., school speed zones with mandatory-stop crosswalks), which may worsen local air quality. In other cases, improvements may result in more efficient traffic flow (e.g., dedicated left-turn lanes), which can improve local air quality. Overall, the environmental effects may be positive but modest, while the safety-related public health benefits should be significant. Given the lat- ter consideration, performance on this criterion is rated as highly positive. Equityâmoderately positive (uncertain). In terms of environmental justice, an increased emphasis on safety is likely to improve outcomes for all user groups and populations, regardless of income, residence, age, gender, race, or ethnicity.
250 I-95 Corridor Coalition. 2011. Drive Clean, Save Green. http://www. i95coalition.org/i95/CoalitionEcoDrivingCampaign/tabid/216/ Default.aspx accessed December 30, 2011). Isebrands, H. 2009. âCrash Analysis of Roundabouts at High-speed Rural Intersections.â 88th Annual Meeting Compendium of Papers. Transportation Research Board of the National Academies, Wash- ington, D.C. Jones, P. 2003. âEncouraging Behavioural Change Through Marketing and Management: What Can Be Achieved?â Presented at the 10th International Conference on Travel Behavior Research, Lucerne, Switzerland. Kittelson and Associates, Herbert S. Levinson Transportation Associ- ates, and DMJM+Harris. 2007. TCRP Report 118: Bus Rapid Transit Practitionerâs Guide. Transportation Research Board of the National Academies, Washington, D.C. LACMTA and Caltrans. Undated. I-405 Sepulveda Pass Improvements Project: Project Benefits Fact Sheet. Minikel, E. 2011. âCyclist Safety on Bicycle Boulevards and Parallel Arterial Routes in Berkeley, California.â 90th Annual Meeting Com- pendium of Papers. Transportation Research Board of the National Academies, Washington, D.C. Naumann, R. B., A. M. Dellinger, E. Zaloshnja, B. A. Lawrence, and T. R. Miller. 2010. âIncidence and Total Lifetime Costs of Motor Vehicleâ Related Fatal and Nonfatal Injury by Road User Type, United States, 2005.â Traffic Injury Prevention, 11 (4): 353â360. NHTSA, National Center for Statistics and Analysis. 2010. Traffic Safety Facts: Highlights of 2009 Motor Vehicle Crashes. DOT HS 811 363. NHTSA. 2012. Traffic Safety Facts: Bicyclists and Other Cyclists. DOT HS 811 624. NSTIFC. 2009. Paying Our Way: A New Framework for Transportation Finance. Washington, D.C. Obenberger, J. 2004. âManaged Lanes,â Public Roads, 68 (3): 48â55. Olszewski, P. 2007. âSingapore Motorisation Restraint and its Implica- tions on Travel Behaviour and Urban Sustainability.â Transporta- tion, 34 (3): 319â335. PierPASS. Undated. PierPASS: Rules, Regulations and Rates. http:// pierpass.org/offpeak-information/rules-regulations-and-rates/ (accessed March 22, 2012). Pisarski, A. and F. Council. 2010. âFuture View of Transportation: Implications for Safety,â White Paper No. 1 for Toward Zero Deaths: A National Strategy on Highway Safety. U.S. Department of Trans- portation. POLB. Undated. Clean Trucks Program. http://www.polb.com/ environment/cleantrucks/default.asp (accessed January 20, 2012). Poole, R. W. 2010. âConditions & Performance Report Breaks New Ground.â Surface Transportation Innovations. 78. Poole, R. W. 2012. âExpress Toll Lanes in High Gear.â Surface Transpor- tation Innovations, 101. Puget Sound Regional Council. 2008. Traffic Choices Study â Summary Report. RITA. 2010. Achieving the Vision: From VII to IntelliDrive. RITA. 2011. Intelligent Transportation Systems Benefits, Costs, Deploy- ment, and Lessons Learned Desk Reference: 2011 Update. RITA. 2012a. Integrated Corridor Management. http://www.its.dot. gov/icms/ (accessed April 9, 2012). RITA. 2012b. Connected Vehicle Research. http://www.its.dot.gov/ connected_vehicle/connected_vehicle.htm (accessed April 13, 2012). Santos, G. and B. Shaffer. 2004. âPreliminary Results of the London Congestion Charging Scheme.â Public Works Management & Policy, 9 (2): 164â181. Brown, J. R., E. Morris, and B. D. Taylor. 2009. âPlanning for Cars in Cit- ies: Planners, Engineers, and Freeways in the 20th Century.â Journal of the American Planning Association, Special Centennial Edition, 75 (2): 161â177. Burt, M., G. Sowell, J. Crawford, and T. Carlson. 2010. Synthesis of Congestion Pricing-Related Environmental Impact Analyses â Final Report, FHWA-HOP-11-008. Federal Highway Administration. Cambridge Systematics. 2009. Federal, State and Local Freight Regula- tions. Oregon Department of Transportation. Cambridge Systematics. 2011. Crashes vs. Congestion â Whatâs the Cost to Society? AAA. City of Stockholm. 2006. Facts and Results from the Stockholm Trials. Deeter, D. 2009. NCHRP Synthesis 399: Real-Time Traveler Information Systems: A Synthesis of Highway Practice,. Transportation Research Board of the National Academies, Washington, D.C. Deka, D. 2004. âSocial and Environmental Justice Issues in Urban Transportation.â In S. Hanson and G. Giuliano, eds., The Geogra- phy of Urban Transportation, 3rd edition. Guilford Press, New York, pp. 332â355. Delcan Corporation. 2007. Cross-Town Improvement Project: Freight Travel Demand Management (TDM)âCase Study. Intermodal Freight Technology Working Group. Downs, A. 2004. Still Stuck in Traffic: Coping with Peak-Hour Traffic Congestion. Brookings Institution Press, Washington, D.C. Ecola, L. and T. Light. 2009. Equity and Congestion Pricing: A Review of the Evidence. RAND Corporation, Santa Monica. Fabian, L. J. 2003. âMaking Cars Pay: Singaporeâs State-of-the-Art Con- gestion Management.â Transportation Planning, 18 (1): 1â2, 10. FHWA. Undated. Crash Reduction Factors: Resources. http://safety. fhwa.dot.gov/tools/crf/resources/ (accessed February 24, 2014). FHWA. 2004. Traffic Congestion and Reliability: Linking Solutions to Problems. FHWA. 2008a. Congestion Pricing: A Primer. FHWA-HOP-08-039. FHWA. 2008b. Statewide Opportunities for Linking Planning and Operations. FHWA. 2010. 2008 Status of the Nationâs Highways, Bridges, and Transit: Conditions & Performance Report to Congress. FHWA. 2012a. Proven Safety Countermeasures: Medians and Pedestrian Crossings in Urban and Suburban Areas. FHWA-SA-12-011. FHWA. 2012b. Value Pricing Pilot Program Projects Involving Tolls: Priced Roadways. http://www.ops.fhwa.dot.gov/tolling_pricing/ value_pricing/projects/involving_tolls/priced_roadways/index. htm as of March 27, 2012). Glaister, S. 2007. National Road Pricing: Policy Design and Public Acceptance. Presented at the ITC-CURACAO. Goh, M. 2002. âCongestion Management and Electronic Pricing in Sin- gapore.â Journal of Transport Geography, 10 (1): 29â38. Harwood, D. W., K. M. Bauer, I. B. Potts, D. J. Torbic, K. R. Richard, E. R. Rabbani, E. Hauer, L. Elefteriadou, and M. S. Griffith. 2003. âSafety Effectiveness of Intersection Left- and Right-Turn Lanes.â 82nd Annual Meeting Compendium of Papers. Transportation Research Board of the National Academies, Washington, D.C. Horsley, J. 2006. âThe Role of State DOTs in Managing Urban Goods Movement.â Presented at the Metrans National Urban Freight Con- ference, Long Beach, California. Hovey, P. W. and M. Chowdhury. 2005. Development of Crash Reduction Factors. Ohio Department of Transportation. I-95 Corridor Coalition. 2010. Final Research Report: Administrative and Legal Issues Associated with a Multi-State VMT-Based Charge System.
251 H. J. Sommer, P. Garvey, B. Persaud, and C. Lyon. 2009. NCHRP Report 641: Guidance for Design and Application of Shoulder and Centerline Rumble Strips. Transportation Research Board of the National Academies, Washington, D.C. TfL. 2008. Central London Congestion Charging Impacts Monitoring: Sixth Annual Report. U.S. Department of the Treasury and U.S. Council of Economic Advi- sors. 2012. A New Economic Analysis of Infrastructure Investment. Waller, S. T., N. Jiang, N. Nezamuddin, T. Zhang, and D. Sun. 2011. Safety Implications of Using Active Traffic Strategies on TxDOT Freeways. Texas Department of Transportation. Willoughby, C. 2000. Singaporeâs Experience in Managing Motorization and Its Relevance to Other Countries. The World Bank. Washington State DOT. 2008. Freight Mobility: Joint Report on Washington State Freight Highway and Rail Projects. Schrank, D. and T. Lomax. 2010. 2009 Urban Mobility Report: Six Con- gestion Reduction Strategies and Their Effects on Mobility. Texas Transportation Institute, the Texas A&M University System. Schweitzer, L. A. and B. D. Taylor. 2008. âJust Pricing: The Distributional Effects of Congestion Pricing and Sales Taxes.â Transportation, 35 (6): 797â812. Shatz, H. J., K. E. Kitchens, S. Rosenbloom, and M. Wachs. 2011. High- way Infrastructure and the Economy: Implications for Federal Policy. RAND Corporation, Santa Monica. Shoup, D. 2005. The High Cost of Free Parking. Planners Press, Chicago. Tang, L. and P. V. Thakuriah. 2012. âRidership Effects of Real-Time Bus Information System: A Case Study in the City of Chicago.â Transportation Research Part C: Emerging Technologies, 22: 146â161. Torbic, D. J., J. M. Hutton, C. D. Bokenkroger, K. M. Bauer, D. W. Harwood, D. K. Gilmore, J. M. Dunn, J. J. Ronchetto, E. T. Donnell,