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130 This final toolbox chapter presents a variety of available bus lane strategies. Considerations applicable to all (or most) types of bus lanes are presented first, followed by shorter sections specific to individual types of bus lanes that discuss what sets them apart from other types of bus lanes. Chapter 8 discusses the following strategies: â¢ Bus lanes (generally), â¢ Curbside bus lanes, â¢ Shared bus and bicycle lanes, â¢ Offset bus lanes, â¢ Left-side bus lanes, â¢ Queue bypasses, â¢ Two-way median bus lanes, â¢ Contraflow bus lanes, and â¢ Two-way, single-lane bus lanes. The introduction to Chapter 5 describes how each strategy section is organized. 8.1 Bus Lanes (Generally) Description A roadway lane dedicated exclusively or primarily to the use of buses. Purpose To reduce the delay that occurs when buses must share a lane with other traffic. Bus lanes allow buses to avoid traffic delays when waiting for a gap when exiting bus stops, to bypass queues of through-vehicles stopped at a traffic signal, and (with some types of lanes) to avoid the delay caused by turning vehiclesâ benefits that would otherwise require a package of individual transit-supportive roadway strategies. Applications Bus lanes are typically considered in the following situations: â¢ On urban streets with relatively high bus and general traffic vol- umes, where many buses and their passengers are subject to delay; C H A P T E R 8 Bus Lane Toolbox
Bus Lane Toolbox 131 â¢ In corridors with BRT or other premium bus service, where maximizing bus speeds and reli- ability is a priority; and â¢ On shorter stretches of roadway, allowing buses to bypass a bottleneck or to move to the front of a queue (Kittelson & Associates et al. 2013). Bus lanes may operate full time or during designated hours only. Depending on the available right-of-way and its current use, they can be created by eliminating curbside parking, by con- verting an existing travel lane to bus-only use, by using available space in the roadway median, by widening the roadway, or a combination of these. They may be dedicated to bus use only, they may allow designated vehicles (e.g., taxis, bicycles) to share the lane, or they may allow other vehicles to enter the lane to make right turns or pick up and drop off passengers. Companion Strategies Any of the bus operations strategies described in Chapter 5 are potentially applicable to bus lanes. Prohibiting right turns by general traffic (Section 6.2) results in better bus lane operations (as buses avoid waiting behind right-turning vehicles queued at a red light or waiting for pedestrians to clear the crosswalk) and gives transit agencies considerable flexibility in where bus stops are located (Section 5.1). Passive traffic signal timing adjustments (Section 6.4) can be considered with any bus lane appli- cation; when bus volumes are relatively high (e.g., a bus arrival every other traffic signal cycle or more frequently), timing signals to allow buses to progress in the peak direction of travel may be appropriate. With lower bus volumes, where priority would not be requested nearly every traffic signal cycle, transit signal priority (Section 6.7) is an option. Bus-only signal phases (Section 6.9) may be required to serve bus turning movements that would conflict with through traffic if made from the bus lane. Pre-signals (Section 6.11) are an option for providing a virtual bus lane beyond the point where constraints make it infeasible to continue a physical bus lane. Bus lanes will usually require some degree of enforcement (Section 6.13) to realize their full benefit. It may be beneficial to shift routes serving parallel streets onto the street with a bus lane to use the lane more efficiently; in these cases, bus stops may need to be lengthened (Section 7.2) to accommodate the increased bus volumes. Red-colored pavement (Section 7.4) improves the conspicuity of bus lanes, which helps reduce inadvertent violations of the bus lane by other vehicles. Constraints Potential constraints depend on how the bus lane would be developed and are discussed in detail in the sections of this chapter that describe specific bus lane types. For example, when developing curbside bus lanes (Section 8.2) by removing on-street parking and delivery zones, the needs of adjacent land users that currently rely on those uses of the curb space will need to be considered. When developing interior bus lanes (Section 8.4) by converting a general traffic lane to bus use, it is mainly how the roadway will operate for general traffic with a reduced number of lanes that will need to be considered (although whether some traffic would divert to parallel routes may need to be taken into account). When developing bus lanes in the median of a roadway, whether sufficient space is available for both the bus lanes and bus stops will need to be considered, as will potential issues with removing existing landscaping. Benefits Bus lanes can improve bus travel times and bus travel time variability. The magnitude of the improvement depends on a number of factors, including the ability of buses to avoid delays from right-turning traffic, illegal stopping and parking activity in the lanes by other vehicles, and the
132 A Guidebook on Transit-Supportive Roadway Strategies level of congestion that existed on the roadway prior to the development of the bus lanes. The Transit Capacity and Quality of Service Manualâs procedure for estimating bus speeds estimates that bus lanes in a central business district (CBD) save buses an average 1.8 min per mile relative to mixed traffic operations when right turns are not allowed from the bus lane. When right turns are allowed, buses save an average 1.0 min per mile, and when bus lanes are regularly blocked by illegally parked and stopped vehicles, buses save an average of 0.0 to 0.5 min per mile. In non- CBD environments, bus lanes save buses an average 0.3 min per mile relative to mixed traffic (Kittelson & Associates et al. 2013, derived from St. Jacques and Levinson 2000). Examples of actual bus lane experience summarized in TCRP Report 118: Bus Rapid Transit Practitionerâs Guide found travel time savings of 0.1 to 1.5 min per mile in Los Angeles and Dallas when expressed as a travel time rate, and savings of 34% to 43% in New York and San Francisco when expressed as a percentage. In addition, travel time variability as measured by the coefficient of variation of travel times (the standard deviation of travel time divided by the average travel time) was reduced by 12% to 57% in Los Angeles and New York (Kittelson & Associates et al. 2007). Cost Considerations â¢ Planning and coordination costs. High. Since bus lane projects are implemented over rela- tively long lengths of roadway in comparison to the intersection focus of most other types of infrastructure strategies, stakeholder engagement, traffic analysis, and similar efforts will need to address a corresponding large area. â¢ Capital costs. Low to high, with a large range of potential costs, ranging from installing new striping and pole-mounted signing (low), to providing overhead signing (moderate for each installation), to widening the roadway or reconstructing the roadway median (high). â¢ Maintenance costs. Relatively low if the bus lane is created by restriping an existing lane, in which case there may be some added costs to maintain the striping and new signs. If the bus lane is created by widening the roadway or creating a new facility in the roadway median, then the costs will be high relative to other strategies due to the new pavement area requiring maintenance. â¢ Bus operations costs. Bus lanes are typically implemented to provide a significant time savings for buses and can produce equally significant cost savings when used by high-frequency routes. Note that there is a difference between one route operating on a bus lane at high frequency versus several low-frequency routes that combine to provide a high frequency. The former situation is more likely to result in sufficient time savings to save a bus, although as discussed in Appendix B, lesser time savings can still provide benefits to transit agencies and their passengers. Bus lanes typically require some degree of enforcement to operate effectively, which entails added operating costs (see Section 6.13). â¢ Other user costs. These costs depend on the type of bus lane developed; see the following sections on specific bus lane types for details. Implementation Examples See the sections of this chapter describing specific bus lane types for implementation examples. Implementation Guidance In any bus lane evaluation involving converting a lane to bus use, it is important to consider whether some existing traffic might choose to use a parallel route in the future, thus reducing the overall impact to roadway operations. If a jurisdictionâs experience is that motorists choose
Bus Lane Toolbox 133 alternate routes when long-term road construction projects occur that close traffic lanes, the same will likely occur when a general traffic lane is converted to a bus lane. Full-Time Versus Part-Time Lanes Full-time lanes are easier to practice enforcement on and continue to provide a travel time reliability benefit during hours when general traffic volumes are lower and the bus lane does not provide as much of a travel time benefit relative to mixed-traffic operations. Part-time lanes allow other roadway users to access the lanes at times when bus and general traffic volumes are lower and are often used in conjunction with curbside lanes where the curb space is desired to be used for deliveries and off-street parking during off-peak hours. However, particularly when the curb is used for parking during off-peak hours, regular enforcement (e.g., daily tow truck sweeps) will be needed to ensure that the lane is available for buses when it is most needed. Median bus lanes (Section 8.7) and single-lane reversible bus lanes (Section 8.9) are typically operated as full-time bus lanes. Right-Turn Prohibitions As indicated in the Benefits section, bus lanes lose nearly half of their travel time savings benefit in CBD areas when right-turning traffic is allowed to enter the bus lane prior to intersections. The right-turning traffic frequently has to yield to pedestrians, and these vehicles block the bus lane while waiting for the crosswalk to clear. Nevertheless, it may be impractical to prohibit right turns along the entire length of the bus lane. Options for addressing right turns include: â¢ Providing right-turn lanes to the right of an interior bus lane, for example by using the width taken by the curbside parking lane and adjusting lane widths as needed on the intersection approach. â¢ In CBD areas, prohibiting right turns at minor intersections so as to concentrate right turns at other intersections, where they can be addressed by other transit-supportive strategies. â¢ In suburban areas, implementing access management strategies that reduce the number of access points between intersections. â¢ In areas with a one-way street grid, locating bus stops at intersections where one-way traffic approaches from the right and right turns would be prohibited anyway. â¢ Ending the physical bus lane and creating a virtual bus lane through the use of a queue jump at the previous traffic signal (Section 6.10) or a pre-signal in advance of the intersection (Section 6.11) that allows buses to enter the general traffic lane ahead of other traffic. Shared Use In situations where the number of buses proposed to use the lanes initially is relatively low (even after rerouting other bus routes to the new facility), and the policy environment is less supportive of transit, it may be necessary to make compromises on how the bus lane is used in order to get something implemented. One potential compromise is to allow other authorized users (e.g., non-transit buses, taxis, bicycles) to use the lane to give it a greater appearance of being used and to build support for the bus lanes with other stakeholder groups that would benefit. Visibility Measures that increase the visibility of a bus lane can help reduce the number of inadvertent bus lane violations and make the lane easier to enforce, thus allowing the laneâs travel time and reliability benefits to be maximized. These measures include red-colored pavement (Section 7.4) and overhead signage such as that illustrated in the photograph at the beginning of this section.
134 A Guidebook on Transit-Supportive Roadway Strategies Additional Resources The following resources provide guidance applicable to bus lanes in general. Where appli- cable, the other sections in this chapter list additional resources applying to a specific bus lane type. â¢ Manual on Uniform Traffic Control Devices (FHWA 2009)âChapter 2G discusses bus lane signs as part of a broader presentation of preferential and managed lane signs. Chapter 3D presents pavement markings for preferential lanes, including bus lanes. â¢ Guide for Geometric Design of Transit Facilities on Highways and Streets (AASHTO 2014)â Section 188.8.131.52 provides guidance on justifying the need for bus priority treatments, including bus lanes. Section 5.5 provides design guidance for many types of bus lane, while Section 5.6 provides design guidance for median busways and bus streets. Section 5.7 discusses enforce- ment needs specific to bus lanes. â¢ Designing Bus Rapid Transit Running Ways (APTA 2010)âthis APTA recommended practice provides guidance on selecting and designing an appropriate bus lane type to support BRT. â¢ TCRP Report 165: Transit Capacity and Quality of Service Manual, 3rd Edition (Kittelson & Associates et al. 2013)âChapter 6 provides analytical methods for estimating bus speeds on bus lanes. â¢ TCRP Report 118: Bus Rapid Transit Practitionerâs Guide (Kittelson & Associates et al. 2007)â Chapter 4 provides general cost information (as of 2004) for different bus lane types as well as cost information specific to individual BRT routes in operation at the time of writing. â¢ TCRP Report 90: Bus Rapid Transit, Volume 1: Case Studies in Bus Rapid Transit (Levinson et al. 2003)âthis report provides 26 case study examples of cities with BRT routes in operation at the time of writing, most of which used some sort of bus lane as part of the overall BRT package. 8.2 Curbside Bus Lane Description A bus lane located in the rightmost lane of the roadway and adjacent to the right curb. Purpose To provide basic bus lane benefits without needing extensive capital improvements beyond signing and pavement markings. Applications A typical application is to convert a curbside parking lane to bus-only use on a full- or part-time basis, allowing a bus lane to be developed without removing a general traffic lane. Dual bus lanes, which can be necessary when very high bus volumes (e.g., 100 or more buses per hour) must be served, are a variation of curbside bus lanes. Companion Strategies See the list of generally applicable companion strategies in Section 8.1. Enforcement (Section 6.13) is a particularly important consideration for curbside bus lanes due to their potential use for unauthorized parking, deliveries, and passenger pickups and drop-offs, particularly when the
Bus Lane Toolbox 135 lanes convert to parking during off-peak hours. Queue jumps (Section 6.10) and pre-signals (Section 6.11) are options for creating a virtual bus lane when a physical curbside bus lane needs to end due to downstream constraints on the use of the curb space. Shared curbside bus and bicycle lanes are covered in Section 8.3. Constraints A key constraint is the potentially large number of competing users that also have a stake in how the curb space is used. Competing uses include bus stops, right-turning traffic, park- ing, deliveries, passenger pickup and drop-off, taxi stands, bicycles, service and maintenance vehicles, and usage as a temporary sidewalk when an adjacent building is under construction (AASHTO 2014). Some of these competing uses may be able to be accommodated from other locationsâfor example, on the opposite side of the street, on side streets, or off the street (AASHTO 2014). Benefits See the general bus lane discussion in Section 8.1. Because of the interference caused by right- turning traffic stopped for pedestrians in crosswalks, curbside bus lanes will produce smaller benefits for buses than other bus lane types when right turns need to be accommodated at inter- sections. There will also typically be some degree of illegal driving, parking, or stopping activity in the lane despite active enforcement efforts. Cost Considerations See the general bus lane discussion in Section 8.1. When created by converting an existing lane, curbside bus lanes will generally have lower capital costs than other bus lane types since only signing and pavement marking changes will be needed. Implementation Examples Curbside bus lanes have been implemented in many North American cities, including Columbus, Ohio; Denver, Colorado; Edmonton, Canada; Eugene, Oregon; Las Vegas, Nevada; Miami, Florida; Minneapolis, Minnesota; New Orleans, Louisiana; New York, New York; Ottawa, Canada; Portland, Oregon; Richmond, Virginia; San Antonio, Texas; San Francisco, California; Seattle, Washington; and Spokane, Washington (Danaher 2010, St. Jacques and Levinson 2000). Implementation Guidance The general bus lane discussion in Section 8.1 is particularly applicable to curbside bus lanes since these lanes are most susceptible to pressure to allow other road users at specific times or places. Additional Resources Section 5.5.2 of the Guide for Geometric Design of Transit Facilities on Highways and Streets (AASHTO 2014) provides design guidance for curbside bus lanes. See also the resources generally applicable to bus lanes in Section 8.1.
136 A Guidebook on Transit-Supportive Roadway Strategies 8.3 Shared Bus and Bicycle Lane Description A curbside lane shared part- or full-time by buses and bicycles; other users may also be allowed into the lane at specific times or locations. Purpose To reduce the impact of general traffic on both buses and bicycles when insufficient roadway space is available to provide separate exclusive facilities for the two modes. Applications Shared bus and bicycle lanes have been used where it was desired to assist both bus and bicycle traffic, but right-of-way constraints prevented developing separate bus and bicycle facilities. Buses travel more quickly than in a mixed-traffic environ- ment, while bicyclists are provided with some separation from general traffic (Hillsman et al. 2012). Allowing bicyclists to use the bus lane (1) may generate broader support for developing a bus lane by increasing the number of stakeholders that benefit from the lanes and (2) may, particularly when bus service is relatively infrequent, help reduce the perception that the lane is not being used efficiently. Hillsman et al. (2012) categorized shared bus and bicycle lanes as follows: (1) short segments generally less than 0.5 mile long that have constrained right-of-way (e.g., bridges) and serve to connect or extend bicycle facilities, (2) urban segments that are generally less than 2 miles long and are typically located on key commuter routes to downtowns, and (3) suburban/low-density segments that are generally more than 2 miles long and are typically located on high-volume arterial roadways. Companion Strategies See the list of generally applicable companion strategies in Section 8.1. Some of the traffic signalârelated strategies given in Chapter 6 can be used at the same time to benefit bicycles, including transit signal priority (Section 6.7), bus-only signal phases that do not conflict with parallel bicycle traffic (Section 6.9), queue jumps (Section 6.10), and pre-signals (Section 6.11). Bus-specific signals (Section 6.12) could also benefit bicycle turning movements, particularly when a well-used bicycle route follows the same alignment as the bus route. Bicycle signal heads can be considered to control bicycle movements when bicycle priority will be given in conjunction with bus priority. At the time of writing, bicycle signal heads were permitted by FHWA Interim Approval IA-16 (Lindley 2013), with the condition that jurisdictions submit a written request to FHWA to use them. They are expected to be included in the next edition of the MUTCD. Constraints Roadways with significant uphill grades are not good candidates for relatively narrow shared lanes because the speed differential between bicycles and buses is considerably greater compared to level or downhill roadway sections, and buses would experience greater delay in situations where they could not immediately pass bicyclists. Roadways with a high volume of traffic in the adjacent lane are also not good candidates for relatively narrow shared lanes since buses would frequently have to slow behind bicyclists while waiting for a gap in traffic to move around the
Bus Lane Toolbox 137 bicyclist, and because bicyclists would need to pass stopped buses in the travel lane unless it is possible to route bicycles around bus stops. Benefits See the general bus lane discussion in Section 8.1. Similar to curbside bus lanes, shared bus and bicycle lanes will not provide the same level of benefit as other bus lane types, particularly when right turns need to be accommodated at intersections, and there will typically be some degree of illegal driving, parking, or stopping activity in the lane despite active enforcement efforts. In addition, when the shared lane is too narrow for buses to go around bicycles without encroaching on the adjacent lane, buses may experience a delay waiting for a suitable gap in traffic to pass the bicyclist or while traveling at the speed of the bicyclist. Cost Considerations See the general bus lane discussion in Section 8.1. Shared bus and bicycle lanes will have slightly higher costs than curbside bus lanes due to the extra signs and pavement markings required specific to bicycles. Implementation Examples Hillsman et al. (2012) identified 27 roadways where shared bus and bicycle lanes were being used in the United States as of 2012, plus additional examples of lanes that were being proposed at the time of the research or that had been removed. They also identified examples internationally in Vienna, Austria; Ghent, Belgium; Ottawa, Toronto, and Vancouver, Canada; Paris, France; Geneva, Switzerland; and Edinburgh and London, United Kingdom. Implementation Guidance Applications NACTO (2012) indicates that bicycle lanes âare most helpfulâ (1) when the speed limit is at least 25 mph, (2) on streets with large numbers of buses, and (3) on streets where the motorized vehicle average daily traffic is 3,000 vehicles or more. Based on this guidance, bicycle lanes or other dedicated bicycle facilities would be preferred in most situations where a bus lane might be considered and bicycle traffic needs to be accommodated. Situations where a shared lane might be considered are (1) business districts with speed limits of 20 mph, (2) bus lanes that would be used by a low volume of buses and a low-to-moderate volume of bicycles (to improve perceptions that the lane is being used), and (3) locations with insufficient right-of-way to accommodate bus and bicycle traffic in separate facilities. In the latter case, short sections of shared lane without bus stops would operate better for both buses and bicycles compared to frequently spaced stops across longer sections, unless it is possible to route bicycles around bus stops. Shared-Lane Width A 16-ft lane width allows buses to pass bicycles without encroaching into the adjacent lane (but might encourage right-turning vehicles, if allowed in the lane, to pull in front of stopped buses), while a 14.5-ft width allows bicycles to pass buses without encroaching into the adja- cent lane. However, widths down to 11 ft (i.e., the minimum recommended bus lane width in AASHTOâs Guide for Geometric Design of Transit Facilities on Highways and Streets ) still provide better separation between bicycles and general traffic than occurs in a mixed-traffic envi- ronment and may be appropriate in situations where bus volumes are relatively low (e.g., less than
138 A Guidebook on Transit-Supportive Roadway Strategies one every other traffic signal cycle on average) or in downtown environments where blocks are short and buses travel relatively slowly and are unlikely to pass bicyclists. When more than 16 ft of width is available, consider providing separate bus and bicycle facilities unless local standards specify greater minimum bus or bicycle widths (e.g., 12 and 5 ft, respectively). Wider lanes tend to promote side-by-side automobile driving, increased heavy vehicle use, and higher motor vehicle speeds (AASHTO 2014). Other Considerations Transit staff in Ottawa interviewed for TCRP Project A-39 believed that while shared bus and bicycle lanes are not an ideal solution, they are safer than the before condition where buses, trucks, automobiles, and bicycles would compete for the same space. Shared bus and bicycle lane imple- mentations in Ottawa have experienced increased bicycle volumes, indicating that bicyclists preferred them to the mixed-traffic situation. Some concern has been raised about the potential for buses and bicycles to leapfrog each other in shared lanes since they often travel at similar average speeds in urban environments (Hillsman et al. 2012; AASHTO 2014). A study of the operation of shared bus and bicycle lanes did not find support for the leapfrogging effect except perhaps on one higher-speed roadway that was studied. However, more research is required (Hillsman et al. 2012). Appendix C provides guidance on managing bus and bicycle conflicts at bus stops. See also the general bus lane discussion in Section 8.1. Additional Resources In addition to the generally applicable bus lane references presented in Section 8.1, and Appendix C: Managing Bus and Bicycle Interactions, which includes a literature review on shared bus and bicycle lanes and guidance on developing them, the following resource provides information specific to shared bus and bicycle lanes: â¢ A Summary of Design, Policies and Operational Characteristics for Shared Bicycle/Bus Lanes (Hillsman et al. 2012)âa review of the design and operation of the shared bus and bicycle lanes known to exist in the United States at the time of writing. 8.4 Interior (Offset) Bus Lane Description A bus lane in the interior of the roadway that is typically located to the left of the curb (parking) lane but can also be in another non-curb lane. Purpose Interior bus lanes are typically used to preserve curb space for on-street parking, deliveries, and other uses while providing a space in the roadway that provides priority to buses. Applications Interior bus lanes are potentially applicable when curb space is desired to be preserved for other uses or right-turning traffic is
Bus Lane Toolbox 139 sufficiently high to make separate right-turn lanes desirable. Both situations are common in urban areas; right-turning delays can also be an issue in suburban commercial strips (AASHTO 2014). An interior bus lane is created by converting a travel lane to a bus lane; it thus affects the roadwayâs capacity. AASHTO (2014) recommends having at least two other travel lanes available in the same direction of travel, which would suggest that interior bus lanes would only be an option for six-lane or wider arterial streets and one-way streets with three or more existing travel lanes. However, New York City has had success implementing interior bus lanes on five-lane roadways such as Webster Avenue by maintaining left-turn lanes where needed and allowing right turns to be made from the bus lane at low-volume intersections and from separate right-turn lanes at higher-volume inter- sections (New York City DOT and MTA-NYCT 2014). At the time of writing, New York City was also considering creating an interior bus lane in the second lane from the curb to allow dual right-turn lanes to be developed at a downstream intersection (New York City DOT 2014). Companion Strategies See the list of generally applicable companion strategies in Section 8.1. Interior bus lanes work well in combination with curb extensions (Section 7.5), which can also help increase the amount of available on-street parking since parking does not need to be removed before or after a stop to give buses access to a curbside stop. Traffic control strategies such as left-turn restrictions (Section 6.2) at key intersections can help improve traffic flow in the remaining general-purpose lanes. Constraints The main potential constraint for interior bus lanes is the loss of roadway capacity; thus, this is primarily a strategy to be considered in locations where policy environments permit some degrada- tion of roadway operations. New York City has experienced success with a combination of traffic control strategies (e.g., turn restrictions and other traffic pattern changes) at busy intersections and using short sections of curbside bus lanes to provide two through lanes or dual turn lanes where needed to serve traffic operations requirements (New York City DOT and MTA-NYCT 2014). Benefits See the general bus lane discussion in Section 8.1. Interior bus lanes provide the option for using the curb lane as a right-turn lane at intersections (with any bus stop located on a far-side curb extension), which provides more flexibility for accommodating right turns without significantly affecting bus operations. Thus, interior bus lanes with curb-lane right-turn lanes will operate similarly to curbside bus lanes that prohibit right turns in terms of the impact of turning traffic on buses. Buses traveling in interior bus lanes may experience brief delays associated with vehicle parking maneuvers that buses in curbside bus lanes would not experience, but they are less likely to experience the need to leave the lane to go around vehicles illegally stopped in the lane. General traffic flow benefits from interior bus lanes because parking movements occur from the bus lane rather than a general traffic lane, resulting in smoother general traffic flow between intersections. Cost Considerations See the general bus lane discussion in Section 8.1. Interior bus lanes may require higher capital and maintenance costs than curbside bus lanes due to the potential need for overhead signs to make the bus lane more visible to motorists.
140 A Guidebook on Transit-Supportive Roadway Strategies Implementation Examples Interior bus lanes are New York Cityâs preferred bus lane strategy for its SBS routes. They have also been used in Ottawa, Canada (AASHTO 2014). Implementation Guidance See the general bus lane discussion in Section 8.1. Implementing interior bus lanes on relatively narrow (e.g., four- or five-lane two-way roadways) will likely require a combination of creative transit and traffic engineering strategies. As a result, this strategy is one where it is essential that transit and roadway agency staff work closely together to develop mutually satisfactory solutions. Additional Resources See the general bus lane discussion in Section 8.1 as well as Section 5.5.3 of the Guide for Geomet- ric Design of Transit Facilities on Highways and Streets (AASHTO 2014). In addition, New York City DOT and MTA-NYCT have performed a series of follow-up studies on their SBS routes, most of which include sections with interior bus lanes. These reports are available on New York City DOTâs Bus Rapid Transit website, http://www.nyc.gov/html/brt/html/routes/routes.shtml. 8.5 Left-Side Bus Lane Description A bus lane on the left side of the roadway that is adjacent to the left curb on one-way streets or adjacent to the median on two-way streets. Purpose Left-side bus lanes are typically applied in special-purpose situations where a more conventional location is infeasible. Applications Examples of situations where left-side bus lanes have been used are: â¢ Where attempting to avoid traffic congestion in the right-hand lanes, â¢ In preparation for a downstream left turn, and â¢ Commuter bus routes that operate express (i.e., without stops) for long stretches. Companion Strategies See the list of generally applicable companion strategies in Section 8.1. Median bus lanes (Section 8.7) are a related strategy. If bus stops are to be provided along a left-side bus lane, either boarding islands (Section 7.6) or a bus equipped with doors on both sides (Section 5.5) will be required. Constraints Depending on how the bus lane is developedâby taking parking from the left curb or by converting a general traffic lane to bus useâthe same constraints faced by curbside bus lanes
Bus Lane Toolbox 141 (Section 8.2) or interior bus lanes (Section 8.4), respectively, will apply. When conventional buses will be serving bus stops along a left-side bus lane, sufficient roadway space needs to be available to provide an ADA-compliant boarding island. Benefits See the general bus lane discussion in Section 8.1. Left-side bus lanes avoid right-turning traffic interferences that can be encountered with more conventional bus lanes. Typically, left turns are prohibited from left-side bus lanes, or left-turning traffic is allowed to cross the bus lane into a left-turn bay; therefore, buses do not experience significant interference with left- turning traffic. Cost Considerations See the general bus lane discussion in Section 8.1. Left-side bus lanes will experience slightly higher capital and maintenance costs than curbside bus lanes due to the need for signs to inform motorists on side streets about the presence of the left-side lane. Implementation Examples Left-side bus lanes are provided on several street segments in San Francisco, including portions of Bush Street, Folsom Street, Fremont Street, and Beale Street. Mirabdal and Thesen (2002) describe the operation of another left-side bus lane in San Francisco. Left-side bus lanes with boarding islands are found in Paris, and left-side bus lanes served by buses with doors on both sides are found in the Public Square area in downtown Cleveland, Ohio (AASHTO 2014) and on the one-way couplet portion of Pioneer Parkway in Springfield, Oregon. Implementation Guidance Motorists turning onto a street with a left-side bus lane will likely need special signs to indicate which lane(s) they should turn into (AASHTO 2014). See also the general bus lane discussion in Section 8.1. Additional Resources Section 5.5.5 of the Guide for Geometric Design of Transit Facilities on Highways and Streets (AASHTO 2014) provides design guidance for left-side bus lanes. See also the resources generally applicable to bus lanes in Section 8.1. 8.6 Queue Bypass Description A relatively short bus lane that allows buses to move to the front of the line at a bottleneck, where they then merge into the adjacent general traffic lane. Purpose To avoid delays caused by waiting in the general traffic queue to pass the bottleneck.
142 A Guidebook on Transit-Supportive Roadway Strategies Applications Queue bypasses are potentially applicable anywhere a traffic bottleneck is created intentionally (e.g., freeway ramp meters, toll plazas) or as a result of constrained right-of-way that reduces roadway capacity (e.g., where two lanes merge into one prior to a narrow bridge or underpass). Queue jumps can also be applied on a temporary basis to maintain bus travel times through work zones where roadway capacity is temporarily reduced (AASHTO 2014). Although it is possible to locate a bus stop along a queue bypass, they are more commonly used on sections of a route where buses do not stop. Companion Strategies Queue jumps (Section 6.10) and pre-signals (Section 6.11) are related strategies, but these rely on traffic signal control to merge buses into the general traffic lane. Shoulder use (Section 7.3) is another related strategy. See also the general bus lane discussion in Section 8.1. Constraints When the bottleneck is created intentionally, such as at a ramp meter, there needs to be suf- ficient right-of-way available to provide a bypass lane long enough for buses to avoid the queue in most circumstances. When the bottleneck is created by a roadway capacity constraint, it might be possible to take a general traffic lane to create the queue bypass lane since this has the effect of moving the general traffic merge point upstream but typically does not affect general traffic delay (the time spent waiting in the queue simply occurs at a different point on the roadway). However, as the back of the queue also moves upstream, there needs to be sufficient space to store the queue without it spilling back into upstream intersections. Benefits The magnitude of the benefit depends on how much delay general traffic experiences at a bottleneck, which in turn depends on the degree to which roadway demand exceeds capacity. The benefit might be a time savings on the order of 1 min at a freeway ramp meter to 10 min or more in the case of a severe capacity constraint on an arterial roadway. Travel time variability would also be expected to improve. Cost Considerations See the general bus lane discussion in Section 8.1. The overall project cost will often be lower than for other kinds of bus lanes because queue bypass projects tend to be shorter, but the cost will be similar to other types of bus lanes when calculated on a per-mile basis. Capital and main- tenance costs will depend on whether new pavement is required to create the lane or whether an existing lane is converted to bus use only. Implementation Examples Many examples exist of ramp-meter queue bypasses to serve bus routes entering freeways from surface streets. The bus/high-occupancy vehicle bypass lanes at the San Francisco Bay Bridge toll plaza in Oakland, California, is an example of bypass lanes that can save buses many tens of minutes during peak periods. Arterial queue bypasses in North America are not well- documented (and finding them is complicated by the fact that the terms queue jump and queue bypass are often used interchangeably), but international literature (e.g., U.K. Department for Transport 2004, Public Transport Authority of Western Australia 2011) includes examples of
Bus Lane Toolbox 143 queue bypasses being used on approaches to narrow bridges and underpasses and in congested city centers. Implementation Guidance See the general bus lane discussion in Section 8.1. The main implementation criterion is that the queue bypass lane should start before the point that buses reach the back of the general traffic queue to allow buses to proceed without delay. Additional Resources See the general bus lane discussion in Section 8.1. 8.7 Median Bus Lane Description Lanes reserved for the exclusive use of buses. These lanes are located in the middle of a roadway and are often separated from other traffic by curbs or landscaped islands. Purpose To provide buses with an exclusive running way within a roadway, free from other traffic interference, except at signalized intersections. Applications Median bus lanes are typically used on BRT routes where the highest possible bus speeds and travel time reliability are desired. Similar to median-running light rail transit, they also help improve the visibility of transit service and the priority given to it. Companion Strategies Turning movements from a median bus lane at a signalized intersection will definitely require a bus-only signal phase (Section 6.9), and through movements will often require one, depending on how general traffic left turns are accommodated. See also the generally applicable companion strategies described in Section 8.1. Constraints After cost, the primary constraint to be addressed is the availability of right-of-way to accom- modate both median bus lanes and stations along the bus lanes. Depending on the degree of separation of the bus lanes from other traffic and the need to accommodate bus turns from the bus lanes, median bus lanes typically require three to four lanes of width (AASHTO 2014). In addition, a sufficient number of through and turning general traffic lanes need to be maintained at intersections, and width may also be required for bicycle facilities, on-street parking, or other design features. The constraints associated with bus-only signal phases (Section 6.9) will also be applicable.
144 A Guidebook on Transit-Supportive Roadway Strategies Benefits Median bus lanes remove the primary sources of traffic interference (e.g., right-turning traffic, parking, delivery activity) that other types of bus lanes can experience. When physically separated from general traffic by curbs or islands, the potential for unauthorized use is very low except for the possibility of vehicles accidentally turning left into the bus lanes at a signalized intersection. As a result, median bus lanes promote good bus travel time reliability and remove most potential sources of bus delay other than traffic signal delays. One potential minus of median bus lanes with respect to bus delay is the need to accommodate general traffic left turns. This in turn may reduce the amount of green time available for bus movements compared to bus operations in a curbside or interior bus lane, resulting in more bus delay waiting for a âgoâ signal indication. The degree to which bus signal delay is increased will depend on a combination of the traffic signal timing and phasing, the bus stop location at the intersection, and the location of the left-turn lane relative to the bus lanes; it is best determined through simulation. Cost Considerations See the general bus lane discussion in Section 8.1. Median bus lanes are typically the most expensive bus lane option due to the extensive street reconstruction required to adequately separate the bus facility from general traffic and the need to provide stations and pedestrian access to those stations within the street median. Implementation Examples â¢ Cleveland, Ohio. The Health Line BRT route operates in median bus lanes on Euclid Avenue. It uses buses with doors on both sides that can serve island platforms between the bus lanes or side platforms to the right of the bus lanes. â¢ Eugene and Springfield, Oregon. The EmX BRT service operates in median bus lanes on a portion of Franklin Boulevard in Eugene and Pioneer Parkway in Springfield. It uses buses with doors on both sides that serve both island and side platforms. â¢ Richmond, British Columbia. The former 98 B-Line BRT route from Vancouver to Richmond operated in median bus lanes on No. 3 Highway. The bus lanes were removed around 2009 when the elevated Canada Line rail line was constructed in the same corridor. â¢ South America. Many South American BRT systems feature extensive use of median busways (Levinson et al. 2003). â¢ MalmÃ¶, Sweden. The MalmÃ¶expressen BRT line that opened in 2014 features median bus lanes constructed in a constricted right-of-way environment in the central portion of Swedenâs third-largest city (Wedeby et al. 2014). Implementation Guidance AASHTO provides extensive design guidance on median bus lanes. Some key considerations are: â¢ Degree of separation from traffic. The more difficult it is for other traffic to access the bus lanes, the better the resulting bus operations will be. At the same time, other considerations, such as available street width, the need to accommodate emergency vehicles, and snowplowing operations may require a reduced level of separation. In order of increasing effectiveness, poten- tial types of separation are lane markings, rumble strips, raised half-globes, raised mountable curbs, flexible posts, concrete barriers, and raised median islands (AASHTO 2014). â¢ Station locations. In a constrained right-of-way, locating stations on the far side of intersections allows a station, two bus lanes, and a general traffic left-turn lane to be provided within a consis- tent right-of-way envelope (i.e., without shifting the bus lanes from side to side). Options in
Bus Lane Toolbox 145 an even more constrained right-of-way include midblock stations served by signalized pedestrian crossings, island platforms served by buses with doors on both sides, and prohibiting left turns. Station platforms need to provide sufficient width to meet ADA requirements and to provide sufficient waiting and circulation space for passengers. â¢ General traffic left-turn accommodations. A common option is to provide a left-turn lane to the right of the bus lane at signalized intersections and to provide individual signal phases for general through traffic, general left-turning traffic, and buses. Buses receive less green time than through traffic under this arrangement. For one midblock BRT station in MalmÃ¶, Sweden, a queue jump in conjunction with a signalized pedestrian crossing was planned to allow the bus lane to cross the left-turn lane entrance without conflict. In this arrangement, the left-turn lane would be to the left of the bus lane at the downstream intersection, and buses could move at the same time as parallel through traffic. Another option is to prohibit left turns (e.g., forcing traffic to turn left at another less-constrained intersection or to make three rights). Allowing traffic into the bus lane to make left turns âis generally undesirableâ (AASHTO 2014). â¢ Bus turning accommodations. The implementation guidance for bus-only signal phases (Section 6.9) includes guidance specific to median bus lanes. â¢ Pedestrian access and crossing movements. Pedestrian access to stations (including the need for accessible pedestrian signals) and the potential need to accommodate midblock pedestrian crossings will need to be addressed as part of the median bus lane design. The potential for illegal pedestrian crossing activity and the possible need for countermeasures will also need to be considered (AASHTO 2014). Additional Resources Section 5.6 of the Guide for Geometric Design of Transit Facilities on Highways and Streets (AASHTO 2014) provides design guidance for median bus lanes. TCRP Report 117: Design, Operation, and Safety of At-Grade Crossings of Exclusive Busways (Eccles et al. 2007) provides guidance on providing pedestrian access to median bus lanes. See also the resources generally applicable to bus lanes in Section 8.1. 8.8 Contraflow Bus Lane Description A bus lane provided in the opposite direction of normal traffic flow on a one-way or divided street. Purpose To provide buses with a more direct routing through a one-way street grid, to keep both directions of a route on the same street, to take advantage of available capacity in the opposite direction of travel, or a combination of these. Applications Typical applications of contraflow bus lanes are: â¢ One-block sections of bus lane that allow a bus to conveniently reverse direction at the end of its route; â¢ Longer sections of bus lane that allow bus service to be provided in both directions on a one- way street, to retain existing two-directional bus service when a street is converted to one-way
146 A Guidebook on Transit-Supportive Roadway Strategies operation, to reduce the number of turns required for buses along their route, to make it easier for non-familiar riders to locate bus stops, or a combination of these; and â¢ Part-time or reversible lanes that take advantage of spare capacity in the opposite direction of travel when traffic flows on a street are highly directional (e.g., heavy toward downtown in the morning and heavy away from downtown in the afternoon) (AASHTO 2014). Companion Strategies Depending on the way the contraflow bus lane is developed, turning movement restrictions (Section 6.2) may be required to prevent potential conflicts between buses and other motor vehicles. Red pavement coloring (Section 7.4) may be desirable to improve the conspicuity of lanes at intersections (to deter motorists from turning into the bus lane by mistake) and between intersections (so that if pedestrians jaywalk, they are at least more aware of the possible presence of buses). Bus signal faces (Section 6.8) may be required to control contraflow buses at signalized intersections. See also the generally applicable companion strategies described in Section 8.1. Constraints Developing a contraflow bus lane requires converting a general traffic lane to bus-only use. If a street only has two travel lanes in the direction of travel prior to conversion, there may be insufficient capacity to accommodate traffic in the remaining lane without removing on-street parking and adjusting lane widths to preserve two travel lanes in the normal direction of flow. Streets with three or more lanes are more promising candidates, particularly when good signal progression is provided in the direction of normal flow. Contraflow bus lanes on one-way streets normally require prohibiting parking and deliveries on the side of the street used by buses and thus have similar potential issues as curbside bus lanes (Section 8.2). Contraflow bus lanes on one-way streets that operate on the left side of the street from a busâs perspective (i.e., on the opposite side of the street from where they would be if the street was two-way) are in an unexpected location from the point of view of motorists and pedestrians and require particular attention to drawing roadway usersâ attention to approaching buses (AASHTO 2014). Part-time contraflow lanes typically require a strong directional split of traffic (e.g., 2â3 or more of the roadwayâs traffic in the peak direction) and the ability to prohibit left turns during hours when the contraflow lane is in operation (AASHTO 2014). Part-time contraflow or reversible operation on arterial streets is not common in the United States, and an extensive outreach effort to motorists may be required as part of the implementation. Benefits Contraflow bus lanes on one-way streets typically operate free of turning-traffic, parking, and delivery conflicts and tend to be self-enforcing (AASHTO 2014). Part-time contraflow lanes allow buses to avoid traffic congestion in the normal-flow lanes. See also the general bus lane discussion in Section 8.1. Cost Considerations Contraflow bus lanes to the right of opposing traffic would have costs similar to curbside bus lanes. Contraflow lanes where buses operate on the left side of the street may require greater separation from traffic (e.g., pylons, curbing) to keep traffic from inadvertently entering the lane and will require extra measures to draw pedestriansâ attention to buses approaching from an unexpected direction. Part-time contraflow lanes may require overhead lane control signals (an additional capital and maintenance cost relative to other bus lane types) or daily installation
Bus Lane Toolbox 147 and removal of pylons (an additional operating cost relative to other bus lane types). See also the general bus lane discussion in Section 8.1. Contraflow lanes developed on streets as part of a conversion from two-way to one-way oper- ation have experienced a drop in crashes, while contraflow lanes developed on existing one-way streets have sometimes experienced an increase in crashes (AASHTO 2014). Implementation Examples Examples of cities with contraflow bus lanes on one-way streets include Chicago, Illinois; Los Angeles, California; Minneapolis, Minnesota; Montreal, Quebec; New York, New York; and Orlando, Florida (AASHTO 2014, Corby et al. 2013). Some express bus routes in Honolulu, Hawaii, use part-time contraflow lanes on arterial streets; however, these lanes are also open to general traffic. Part-time contraflow lanes were also used on Boulevard Pie-IX in Montreal, Quebec, until the early 2000s; at the time of writing, the street was being reconstructed to implement median bus lanes. Implementation Guidance AASHTO (2014) provides design guidance on contraflow bus lanes. A key design consideration, particularly for contraflow lanes that operate on the left side of the street or lanes developed on streets that were previously one-way, is addressing motorist and pedestrian expectancy issues. The main concerns with motorists are turning into the contraflow lane by mistake or making a turn without looking for an oncoming bus. Special lane-use signs and red pavement coloring (Section 7.4) can help with the former; prohibiting conflicting turns or allowing them only on a protected signal phase can help with the latter. For pedestrians, a key concern is that pedestrians crossing at unsignalized or midblock locations (legally or illegally) may spot a gap in the general traffic flow and step off the curb without looking for a bus coming from the opposite direction. Again, red pavement coloring can improve the visibility of the bus lane. Signs and pavement markings can also be applied at legal crossing points; barrier treatments that discourage illegal crossings or strict enforcement of jaywalking laws may be required in locations where jaywalking is prevalent (AASHTO 2014). Outreach and education efforts directed to seniors and persons with disabilities may also be required. Contraflow bus lanes may require more width than other types of bus lanes in the following situations: â¢ Lanes that will be used by many buses during peak hours (to provide room for buses to pass a disabled bus in the contraflow lane); â¢ Lanes where curbs or other barriers exist on both sides of the lane (to give buses more maneu- vering room); and â¢ Lanes in environments where pedestrian jaywalking is common (to give buses more maneu- vering room) (AASHTO 2014). The Implementation Guidance section for reversible bus lanes (Section 8.9) discusses strategies for notifying road users of approaching buses; these strategies may also be applicable to contraflow bus lanes. Additional Resources Section 5.5.4 of the Guide for Geometric Design of Transit Facilities on Highways and Streets (AASHTO 2014) provides design guidance for contraflow bus lanes. Chapter 4M of the MUTCD (FHWA 2009) addresses lane-use control signals. See also the resources generally applicable to bus lanes in Section 8.1.
148 A Guidebook on Transit-Supportive Roadway Strategies 8.9 Reversible Bus Lane Description A single bus lane that serves buses operating in both directions. Purpose To provide a bus lane on a roadway where right-of-way con- straints prevent providing bus lanes in both directions. Applications There are two primary ways that a reversible bus lane can be implemented: 1. Using time-of-day controls so that the bus lane operates (for example) inbound in the morning and outbound in the after- noon. Buses traveling in the off-peak direction use the general traffic lane. 2. Using bus signals to control access to the bus lane in one direc- tion of travel at a time, with the direction alternating back and forth as needed to serve buses. Buses always use the bus lane. Reversible bus lanes have been implemented in street medians, with curbs or landscaped islands separating the lanes from other traffic; in the center of a street, separated only by lane markings (e.g., in place of a center two-way left-turn lane); and on one side of a one-way street, separated only by lane markings. Companion Strategies Reversible bus lanes separated from general traffic only by striping are preferably highlighted in some way, such as with red pavement coloring (Section 7.4) or using Portland cement con- crete for the bus lane to create a contrast with darker asphalt concrete in the general traffic lanes. When signals are used to control bus access to the reversible bus lane, transit signal faces (Sec- tion 6.8) are typically used to indicate to buses when they may proceed. Transit signal faces and bus-only signal phases (Section 6.9) are frequently used at signalized intersections along the bus lane. Turn restrictions (Section 6.2) that prevent general traffic from crossing the bus lane may also need to be considered. ADA-compliant boarding islands (Section 7.6) will be required to serve stops along bus lanes in the center of the street. See also the generally applicable companion strategies described in Section 8.1. Constraints Turning movements across the reversible bus lane may need to be restricted to eliminate or reduce the potential for crashes between buses and turning motorists that did not expect a bus to come from either direction in the lane. Two-directional, single-lane operation that alternates back and forth can greatly reduce the bus frequency that can operate in the bus lane, with the impact increasing as the distance between passing opportunities increases. Converting a curb lane to a reversible bus lane may have impacts on adjacent land uses similar to those of a curbside bus lane (Section 8.2).
Bus Lane Toolbox 149 Benefits Reversible bus lanes typically prohibit turns from the bus lane and thereby provide benefits similar to those of median bus lanes (Section 8.7), interior bus lanes (Section 8.4), or curbside bus lanes with right turns prohibited (Section 8.2), depending on the design of the reversible lane. When protected turn phases are required to serve general traffic turns across the reversible lane, the amount of green time available for buses may be less than that available for general through traffic, resulting in longer bus signal delays. When the lane alternates direction through the use of signals, buses may experience delay waiting for a bus from the opposite direction to clear the reversible lane segment. Consequently, ensuring that buses arrive on schedule at the start of a reversible lane segment to use their designated time slot, and designing passing opportunities in appropriate locations for the planned headway to minimize potential waits, are critical factors to address for buses to gain a travel time benefit (and avoid a travel time disbenefit) from the use of a reversible lane. See also the general bus lane discussion in Section 8.1. Cost Considerations Reversible bus lanes are typically more expensive to construct than similar types of non- reversible bus lanes (i.e., median, interior, or curbside lanes), particularly when a signal system to control bus access to the lane is required. More signs are needed relative to other types of bus lanes to warn other road users of the unusual operation, and the use of red-colored pavement (Section 7.4) or contrasting pavement colors is suggested to improve the bus laneâs conspicuity. Time-controlled reversible bus lanes may require two sets of bus stop infrastructure at each stopâ one for when buses are using the bus lane and one for when buses are using the general traffic lane. See the general bus lane discussion in Section 8.1. Implementation Examples â¢ Eugene, Oregon. Eugene uses reversible bus lanes in sections of the street median on Franklin Boulevard used by its first BRT route, although, to improve bus operations, the length of one of the single-lane segments has been reduced since the line opened. Eugene uses a curbside reversible lane on a one-way portion of East 11th Avenue, with a passing opportunity provided at a station. Eugene uses a center bus lane on a two-way portion of East 11th Avenue, with a passing opportunity provided at a station. Turns across the bus lane are allowed, with special signs used to warn roadway users to look for buses coming from both sides or from behind (see the Implementation Guidance section). When the line first opened, reversible operation was also used in the center of the street on portions of East 10th Avenue and Mill Street, but the route was later split, with one direction on East 11th Avenue and the other direction on East 10th Avenue, in part due to a lack of passing opportunities in this section that affected bus operations. â¢ West Valley City, Utah. UTA operates the 35M MAX bus rapid transit route in the Salt Lake City region. A 1-mile portion of the route operates in bus lanes in the street median of 3500 S. At signalized intersections, the bus lane narrows to a one-lane reversible alignment because right-of-way was required to provide dual left-turn lanes or right- and left-turn lanes for general traffic. Bus access to the reversible sections is controlled by a bus signaling system. â¢ Lund, Sweden. A time-controlled reversible bus lane operates in the center of three-lane TornavÃ¤gen northeast of the city center. Buses traveling toward the city center use the lane between 5:00 a.m. and 12:30 p.m., while buses traveling away from the city center use it between 12:45 and 11:00 p.m. Buses travel in the general traffic lanes during times when they are not permitted in the reversible lane (City of Lund 2011). The street has relatively few access points, and most unsignalized intersections and all driveways that do exist are controlled for right-in,
150 A Guidebook on Transit-Supportive Roadway Strategies right-out turns only. The one traffic signal in this stretch serves buses on a special bus phase; general traffic is allowed to make left turns from both streets at this location. Reversible opera- tion ends at the south end at a three-leg unsignalized intersection where left turns from and across the bus lane are permitted; the bus lane continues in the inbound direction only past this point, ending just before a traffic signal. Buses merge into the general traffic lane at this point in preparation for making a left turn. At the north end of the bus lane, the general traffic lane merges with the bus lane; general traffic is required to yield to buses. Implementation Guidance Reversible bus lanes may be an option where right-of-way constraints prevent the implemen- tation of bus lanes for both directions of travel, but they require attention to certain issues not found with other bus lane types. Lane Control Controlling a reversible bus lane by time of day may be an option when traffic on the street is highly directional (e.g., 70/30 in the peak direction) so that buses experience minimal traffic delays when using the general traffic lane(s) in the off-peak direction. As this option requires two sets of bus stop infrastructure at each bus stopâone for when buses are using the bus lane and one for when buses are using a general traffic laneâit is important that passengers be able to easily figure out where and when to wait for a bus. It may also be necessary to consider the possibility that passengers may try to dash across the street if they see the bus approaching the other stop and to develop appropriate countermeasures. Signal control will be required when bidirectional operation is desired throughout the day. This type of operation requires special attention to coordinating the planned bus headway, the locations where passing opportunities are provided, and the bus schedule, as well as implementing upstream transit-supportive roadway strategies that help buses arrive at a single-lane section on schedule. The goal is to have buses that are traveling in opposite directions meet in sections where passing is possible and not at the single-lane section to avoid one bus being delayed while the other bus uses the single-lane section. The rail transit single-track capacity method given in the TCQSM (Kittelson & Associates et al. 2013) can be applied to evaluating single-lane bidirectional bus lane capacity by eliminating the rail-specific elements of the method, such as the time to move switches. In general, the longer the single-lane section, the greater the number of single-lane sections along a route, the greater the traffic signal delay within a single-lane section, the lower the speed limit, and the less-reliable the bus arrivals at the start of a single-lane section, the fewer buses on a route that can be served in an hour without creating bus bunching. For a case where the speed limit is 30 mph, buses arrive within 2 min of schedule, and no stops are made within the single-lane section to serve passengers or for traffic signals, a 0.5-mile-long bidirectional single bus lane could support up to 10 buses per direc- tion per hour on a route (i.e., 6-min headways) if the buses are scheduled to avoid arriving at the single-lane section at the same time. As conditions worsen from this case (e.g., traffic signal delays, less-reliable service, a longer single-lane section, a lower speed limit), the minimum bus headway on a route would increase. Note that it is possible to send more than one bus at a time in the same direction through a single-lane section. For example, for the condition given in the previous paragraph, two routes could operate in the section, each with 6-min headways, and not have bus bunching occur on the individual routes. Because this type of operation will form platoons of buses operating on different routes, bus stops will need be designed to accommodate multiple buses at the same time (Section 7.2).
Bus Lane Toolbox 151 Turn Restrictions General traffic turning movements are not suggested to be allowed from reversible bus lanes due to the potential for head-on or sideswipe collisions with buses. Ideally, turns would also be pro- hibited across reversible bus lanes since this would eliminate potential busâautomobile conflicts. However, when prohibiting turns is not feasible, the following are other options: â¢ Protected turn phases at signalized intersections. Left and right turns from the bus laneâs street are preferably made using protected (i.e., arrow) phases to reduce the possibility of conflicts. This option reduces the amount of green time available for bus movements, which will increase bus signal delay. â¢ Prohibiting right turns on red at signalized intersections. Right turns on red that cross a reversible bus lane can be prohibited, either full-time or through the use of blank-out displays that activate when a bus is approaching. â¢ Part-time turn prohibitions. Blank-out turn-prohibition signs can be used at times when a bus is approaching to prohibit turns that cross the bus lane at any intersection. â¢ Adding signs to warn side-street road users of potentially conflicting buses. A proposed new MUTCD chapter on busway grade crossings includes a requirement for a busway crossing warning consisting of a yellow diamond-shaped sign with the picture of a bus, with the option for a yellow rectangular sign underneath with a double-headed arrow indicating two-way operation (NCUTCD 2014a). Until included in the MUTCD, agencies would need to apply to FHWA to experiment with the signs (see Appendix D). â¢ Adding blank-out signs to warn road users of potentially conflicting buses. A proposed new MUTCD chapter on busway grade crossings includes the option for a blank-out sign that displays a flashing picture of a bus, the text âBus Coming,â or both when a bus approaches (NCUTCD 2014a). This sign would be used similarly to existing blank-out signs warning of approaching light rail trains (MUTCD, Section 8B.19) and could be used in conjunction with main- and side-street turning movements and pedestrian crossings. Until included in the MUTCD, agencies would need to apply to FHWA to experiment with the sign. Audible warnings for the benefit of visually impaired pedestrians could also be considered in conjunction with the blank-out signs. Pedestrians Consideration should be given to drawing pedestriansâ attention to the potential for buses approaching from either direction, particularly when reversible curbside bus lanes are used. The static and active warning signs described previously are potentially applicable, as are pedestrian- focused word messages on the sidewalk (e.g., âLook Both Waysâ), accessible pedestrian signals, and outreach and education efforts directed to seniors and persons with disabilities. When bus stops are located on boarding islands in the center of the street at unsignalized intersections, marked pedestrian crosswalks may be desirable. As discussed earlier in the Lane Control subsection, when two sets of bus stops are provided in conjunction with time-controlled reversible bus lanes, it may be necessary to consider the possibility that passengers may try to dash across the street if they see the bus approaching the other stop and to develop appropriate countermeasures. Additional Resources Chapter 8 of the TCQSM (Kittelson & Associates et al. 2013) provides a method for deter- mining single-track rail transit capacity that is adaptable to determining the minimum headway feasible for reversible bus lane operations. See also the resources generally applicable to bus lanes in Section 8.1.