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1 Summary The Interstate Highway System has conferred both broad and deep benefits on the nation. Not only does it connect and integrate the transcontinental United States, but it also has been pivotal for more than 50 years in shap- ing and supporting the countryâs demographic, spatial, economic, and social development. It functions as the main corridors for passenger and freight movement both within large urban agglomerations and between metropolitan and rural areas. It provides critical connections and services complementary to all of the countryâs other passenger and freight transpor- tation networks and their nodes, including railroads, marine ports, airports, public transit, and local road systems. Because its impacts reverberate across the transportation sector, society, and the economy, it is imperative that the Interstate System not only be preserved and rehabilitated, but also renewed and modernized to adapt to the countryâs changing demographic, economic, climate, and technological landscape. The Interstate Highway Systemâs future is threatened by a persistent and growing backlog of physical and operational deficiencies and by a number of large and looming challenges. Most of its segments are decades old, subject to much heavier traffic than anticipated, and operating well beyond their design life without having undergone major upgrades or reconstruction. These aging and heavily used segments, whose ranks will grow over the next 20 years, are poorly positioned to accommodate even modest projections of future traffic growth, much less the magnitude of growth experienced since the systemâs inception in 1956. As the nation moves further into the 21st century and as transforma- tions in the vehicle fleet and vulnerabilities due to climate change place
2 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM new demands on the countryâs transportation infrastructure, the prospect of an aging and worn Interstate Highway System that operates unreliably is concerning. Unless a commitment is made soon to remedying the systemâs deficiencies and to preparing it for the challenges that lie ahead, there is a very real risk that the system will become increasingly congested; far more costly to operate, maintain, and repair; less safe; incompatible with evolving technology; and vulnerable to the effects of a changing climate and extreme weather. The consequences from these deficiencies will spill over into all the passenger and freight modes that complement and connect to the system. Congress called for the present study to inform pending and future federal investment and policy decisions concerning the Interstate Highway System. Specifically, Congress asked for recommendations on the actions necessary to restore and upgrade the system to meet the growing and shift- ing demands of the 21st century, through the next 50 years. The studyâs findings, summarized below, point to the need for a major reinvestment in the system. Collectively, they serve as a call for actionâcarried out not through a series of incremental steps to repair the current system but through a concerted and adequately funded national campaign of system renewal and modernization patterned after the visionary program that ini- tially produced the Interstates. LOOMING CHALLENGES The committee identified major challenges confronting decision makers as they contemplate the future of the Interstate Highway System. These chal- lenges include â¢ Commencing the enormous task of rebuilding the systemâs pave- ments, bridges, and other assets and their foundations before they become unserviceable and less safe; â¢ Meeting the growing demand for investments in physical capacity, especially on the urban portions of the system, and for more active and innovative management of this capacity in large metropolitan areas that continue to experience most of the countryâs population and economic growth; â¢ Ensuring that the system remains responsive to, and aligned with, continued changes in the geography and composition of the coun- tryâs population and economy, and that its connections with the other modes of local, interregional, and long-distance transporta- tion are maintained and strengthened; â¢ Continually improving system safety as traffic volumes increase, new highway and vehicle technologies are introduced, and the system is modified to increase capacity and throughput;
SUMMARY 3 â¢ Ensuring that the system is robust and adaptable to changing vehi- cle technologies, and avoiding premature investments in assets and the introduction of standards that would hinder or even foreclose useful development pathways; â¢ Adopting funding mechanisms that are equitable and efficient, do not unduly impose the burden of payment on future generations or on less financially equipped groups, and do not disadvantage or divert resources from other highways and modes of passenger and freight transportation; and â¢ Developing and implementing strategies for incorporating future climate conditions into infrastructure and operations planning, starting with the development of design and construction standards that assume greater frequency and severity of extreme weather events. AN INVESTMENT IMPERATIVE Because of the uncertainties associated with forecasting developments far into the future, specific uncertainties about the pace and form of motor ve- hicle automation, and the absence of appropriate modeling tools and data, the committee restricted its time horizon to the next 20 years for estimating system investment needs. During this period, the transition to vehicle auto- mation is expected to remain at an early stage and have limited effects on Interstate travel. Investment needs over the 20-year horizon are likely to be dominated by a necessity to rehabilitate and reconstruct large portions of the Interstate System, which can be more confidently predicted than needs arising from changes in system use. Most of the Interstate Highway System has far exceeded its design life or will do so over the next 20 years. Only limited planning and budget- ary preparations have been made to fix the deterioration that has already occurred and to prevent the physical and operational deficiencies that will ensue. Recent combined state and federal capital spending on the Interstates has been on the order of $20â$25 billion annually (see Figure S-1). The information gathering, modeling, and case studies that informed this study indicate that this level of spending is too lowâby at least 50 percentâjust to proceed with the long-deferred rebuilding of the systemâs aging and deteriorating pavements and bridges. The committee estimates that invest- ments averaging more than $30 billion per year will be needed over the next 20 years to repair and reconstruct these assets from damage already done and that is forthcoming from the effects of age and further use. Figure S-1 shows how these rehabilitation and reconstruction investment needs do not change much across different scenarios of growth in vehicle miles traveled. Along with these substantial investments in pavement and bridge re- habilitation and reconstruction, additional investments will be required to
4 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM expand and manage the Interstate Highway Systemâs capacity to handle future traffic. Investments that will be required to accommodate this traffic demand are much more difficult to project. Significant capacity additions will likely be required because of growth of urban areas that are not well connected to the Interstate System and because of the continued growth of large metropolitan regions. However, the size, location, and timing of these needed additions will depend on a host of factors related to changes in the population and economy, how travelers respond to congestion and the supply of new capacity, whether new capacity is restricted to specific users, and the availability of options other than Interstate travel. Trans- portation agencies, especially in urban areas, may substitute more active operations and demand management measures, such as congestion tolling, for spending on lane widening and other physical additions to Interstate highways, particularly where the acquisition of additional right of way is FIGURE S-1 Estimated spending needs for Interstate highway renewal and mod- ernization over the next 20 years. NOTES: All dollar figures are converted 2016 values. The most recent complete data on Interstate highway spending is for 2014. See Chapter 5 for details on computa- tion methods. VMT = vehicle-miles traveled.
SUMMARY 5 very expensive or unacceptable to local communities. Although connected and automated vehicles are likely to have limited effects on travel demand in the nearer term, expectations about their longer-term impact may influ- ence transportation agency decisions about whether and where to invest in Interstate capacity, especially in 10 to 15 years. In addition to the many uncertainties and interdependencies noted above, the committee found that the available data and models do not have the ca- pability to predict the effects of changes in capacity on travel demand across broad portions of the Interstate network. By stretching the national-level modeling capabilities that do exist and using a range of historically informed rates of growth in future Interstate travel, the committee could, at best, make rough approximations of the magnitude of spending that might be needed for physical and operational capacity improvements over the next 20 years. The models calculate that if travel on the system is assumed to grow at a modest pace comparable to the forecast U.S. population (0.75 percent growth annu- ally), transportation agencies will need to invest an average of $15 billion per year for such improvements. These investments would need to be consider- ably larger, by about 50 to 100 percent, if travel on the system is assumed to grow at a pace closer to recent historical averages (see Figure S-1). Thus, an approximation of the total state and federal spending that will be needed to renew and modernize the Interstates over the next 20 years averages $45â70 billion per year. The figures in this range are 2 to 3 times higher than current spending levels, and even 50 percent higher when only considering the outlays that will be required for the pavement and bridge upgrades that can be projected with higher confidence. However, even these estimated investment levels may be inadequate. Because of the lack of analytical tools and adequate databases, they do not include the funding required to reconfigure and reconstruct many of the Interstate Systemâs roughly 15,000 interchanges, nor do they include the resources needed to make the system more resilient to the effects of climate change, add special- purpose and managed lanes that can allocate system capacity more effi- ciently in and around metropolitan areas, and ârightsizeâ the systemâs scope of coverage through network extensions and in some cases replacement and modification of controversial urban segments. While these investment needs could not be estimated even roughly for this study, they are certain to require billions, and perhaps tens of billions, in additional annual spending. RECOMMENDATIONS The original Interstate Highway Construction Program was underpinned by a long-term, collaborative commitment among the states and the federal government. A comparable partnership is needed to renew and modernize the system and to ensure that it is resilient and responsive to the changing
6 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM demands of users. Central to that partnership is federal leadership and a resolve to restore the Interstate Highway Systemâs premier status and ensure that this status is no longer allowed to obsolesce. The recommendations that follow provide a blueprint for Congress to act on that resolve. Congress should legislate an Interstate Highway System Renewal and Modernization Program (RAMP). This program, presumed to be pursued without sacrificing normal ongoing system maintenance and repair, should focus on reconstructing deteriorated pavements, including their founda- tions, and bridge infrastructure; adding physical capacity and operations and demand management capabilities (e.g., tolling) where needed; and in- creasing the systemâs resilience. RAMP should be modeled after the original Interstate Highway System Construction Program by â¢ Reinforcing the traditional program partnership in which the fed- eral government provides leadership in establishing the national vision for the overall system, the bulk of the needed funding, and overall standards, while states prioritize and execute projects in their continued role as owners, builders, operators, and maintain- ers of the system; â¢ Ensuring that the federal share of project spending is comparable to the 90 percent share of the original Interstate Highway System Construction Program; â¢ Committing the federal government to supporting projects from start to finish, but with a cap on total federal funding (i.e., a cost- to-complete approach); and â¢ Developing transition plans for updating and incorporating stan- dards for system uniformity and safety to accommodate changing vehicle and highway technologies, environmental and climate con- ditions, and usage patterns. Congress should, as a near-term step, (1) increase the federal motor fuel tax to a level commensurate with the federal share of the required RAMP investment, and (2) adjust the tax as needed to account for inflation and changes in vehicle fuel economy. To ensure that the federal governmentâs long-term commitment to RAMP is not threatened by declining fuel tax revenues as the vehicle fleet and its energy sources evolve, Congress should prepare for the need to em- ploy new federal and state funding mechanisms, such as the imposition of tolls or per-mile charges on users of the Interstate Highway System. To provide states and metropolitan areas with more options for raising revenue for their share of RAMP investments and for managing the traffic demand on and operations of Interstate segments that offer limited op- portunity for physical expansion, Congress should lift the ban on tolling of existing general-purpose Interstate highways. As a condition for imposing
SUMMARY 7 those tolls, states should be required to assess their impact on current us- ers and offer alternative mobility options for those users significantly and disproportionately harmed by the tolls. A ârightsizingâ component of RAMP should address current and emerging demands to extend the Interstate Systemâs length and scope of coverage, and to remediate economic, social, and environmental disruptions caused by highway segments that communities find overly intrusive and are not deemed vital to network and intermodal traffic. Congress should direct the U.S. Department of Transportation and the Federal Highway Adminis- tration to develop criteria for such system rightsizing using a consultative process that involves states, local jurisdictions, highway users, and the general public. The criteria and their development should take into account the interest in ensuring â¢ Adequate system connectivity to accommodate network flows of Interstate travel and commerce, including traffic from other impor- tant passenger and freight transportation modes; â¢ System access to growing centers of population and economic activity; â¢ System resilience through redundancy or other means as appropri- ate; and â¢ Responsiveness to national defense needs. CONCLUDING COMMENTS Implementation of the above recommendations, together with the recom- mended complementary actions summarized in Box S-1, would represent a fundamental shift away from a federal policy that has lost focus on the Interstate System and the commitment to funding it adequately. These actions would restore the systemâs premier status within the nationâs high- way program in a manner that is aggressive and ambitious, although by no means novel. Taking these actions would rekindle a tried-and-true federalâstate partnership; reinforce the systemâs long-standing reliance on user fees to provide a fair, adequate, and reliable source of funding; and reassert the forward-looking vision that was instrumental to the genesis of this crucial national asset more than a half-century ago. At that time, the nationâs leaders endorsed a modern highway system that would confer large and lasting societal and economic benefits, a vision whose realization required a strong and continuing national commitment. Today, the nation is experiencing, and can anticipate, new expectations for the systemâs con- dition, performance, and use. Meeting those expectations will require the same forward-looking outlook and commitment that informed the systemâs creationâa rededication to that original vision that reshapes and reequips the system to serve generations to come.
8 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM BOX S-1 A Blueprint for Action Recommendation 1. Congress should legislate an Interstate Highway System Renewal and Modernization Program (RAMP). This program, presumed to be pursued without sacrificing normal ongoing system maintenance and repair, should focus on reconstructing deteriorated pavements, including their foundations, and bridge infrastructure; adding physical capacity and traffic demand and operations management capabilities where needed; and increasing the systemâs resilience. Recommendation 2. A ârightsizingâ component of RAMP should address current and emerging demands to extend the Interstate Systemâs length and scope of cov- erage, and to remediate economic, social, and environmental disruption caused by highway segments that communities find overly intrusive and are not deemed vital to network and intermodal traffic. Congress should direct the U.S. Department of Transportation (U.S. DOT) and the Federal Highway Administration (FHWA) to de- velop criteria for such system rightsizing using a consultative process that involves states, local jurisdictions, highway users, and the general public. Recommendation 3. To better ascertain the spending levels required for RAMP investments, Congress should direct U.S. DOT and FHWA to join with the states to assess the foundational integrity of the systemâs pavements and bridges, and iden- tify where full reconstruction is needed based on accepted life-cycle cost principles. Recommendation 4. To pay for RAMP investments, Congress should, as a near- term step, (1) increase the federal motor fuel tax as needed to a level commen- surate with the federal share of the required investment, and (2) adjust the tax as needed to account for inflation and changes in vehicle fuel economy. Recommendations 5. To provide states and metropolitan areas with more options for raising revenue for their share of RAMP investments and for managing the op- erations of Interstate segments that offer limited opportunity for physical expansion, Congress should lift the ban on tolling of existing general-purpose Interstate high- ways. As a condition for imposing those tolls, states should be required to assess their impact on current users and offer alternative mobility options for those users significantly and disproportionately harmed by the tolls. Recommendations 6. To ensure that the federal governmentâs long-term commit- ment to RAMP is not threatened by declining fuel tax revenues as the vehicle fleet and its energy sources evolve, Congress should prepare for the need to employ new federal and state funding mechanisms, such as the imposition of tolls or per- mile charges on users of the Interstate Highway System. Recommendation 7. To support renewal and modernization investment decisions, Congress should direct, and provide sufficient funding for, U.S. DOT and FHWA to
SUMMARY 9 develop modeling tools and databases that track the full condition of Interstate as- sets, including interchanges, and their reconstruction history; can be used to assess transportation options that can supplement or substitute for additions to Interstate highway capacity; allow for the monitoring and modeling of network-level traffic flows on the Interstate Highway System; and further federal and state understand- ing of the demand for long-distance and interregional passenger and freight travel by highway and other modes. Because these recommended activities are important for guiding reinvestment in the Interstate System, careful consideration should be given to carrying them out in an effective and efficient manner. Recommendation 8. Congress should direct U.S. DOT and FHWA, working with states, industry, and independent technical experts, to start planning the transition to more automated and connected vehicle operations. This effort should entail perform- ing the needed research and updates to Interstate Highway System requirements and standards so as to ensure that basic intelligent transportation system (ITS) instrumentation is adopted on a consistent and system-wide basis, and that the uniformity and other attributes of pavement markings, interchange design, and the like are capable of facilitating eventual Interstate use by connected and automated vehicles. An emphasis should be placed on ensuring that renewal and moderniza- tion projects give full consideration to safety impacts, including the deployment of advanced design and operational features that have demonstrated effectiveness in improving safety, and that cybersecurity protections are incorporated into the designs and upgrades of the Interstate highways and the vehicles that use them. Recommendation 9. Expanding on earlier legislative directives (e.g., the Moving Ahead for Progress in the 21st Century [MAP-21] Act and the Fixing Americaâs Sur- face Transportation [FAST] Act) for transportation agencies to consider resilience in long-term planning, Congress should direct U.S. DOT and FHWA to substantiate that state Interstate highway renewal and modernization projects have fully taken into account the need for resilience. To support these efforts, U.S. DOT and FHWA should be directed to assess the vulnerability of the Interstate Highway System to the effects of climate change and extreme weather; develop standards, in conjunction with states, for incorporating cost-effective resilience enhancements into projects; and develop and maintain a database of cost-effective practices and resilience strat- egies employed by state highway and other transportation agencies, including any funding mechanisms dedicated to support resilience planning and implementation. Recommendation 10. Congress should direct U.S. DOT and FHWA to ascertain the Interstate Highway Systemâs contribution to the countryâs emission of greenhouse gases and recommend options for reducing this contribution in conjunction with re- ductions in other emissions of pollutants. The effort should build on past initiatives, such as legislation requiring states to consider the emissions impacts of capacity expansion and demand-management options, and legislation mandating a federal program to examine the siting of facilities that support alternative-fueled vehicles, such as electric vehicle charging stations located on Interstate highway corridors.