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167 C.1 Introduction Streets used by transit vehicles frequently make desirable corridors for bicycle traffic since these roadways often provide direct access to destinations with relatively few stops required. Given the limited amount of street right-of-way that is often available, a challenge can arise in allocat- ing the right-of-way among the various modes (e.g., transit, bicycle, automobile, pedestrian) using the street. The need to serve bicycle traffic may constrain the options available for implement- ing transit-supportive roadway strategies. Therefore, this appendix provides potential solutions for accommodating both bicycles and buses on streets and at bus stops that are to the benefit of both modes. C.2 Bus and Bicycle Facility Types A number of options are available for on-street bus and bicycle facilities; examples are illustrated in Figure C-1. These options can be categorized by the degree of bus separation from automobile traffic and by the degree of bicycle separation from motor vehicle traffic (including buses). Shared Mixed-Use Lane With a shared mixed-use lane (Figure C-1a), the right traffic lane is shared by buses, other motor vehicles, and bicycles. Buses are slowed by the other users of the lane and may need to use the adjacent lane (when available) to safely pass bicycles. Bus stops can either be offline (i.e., the bus pulls out of the traffic lane into the parking lane or a bus pullout to stop) or online (i.e., no parking lane exists or a curb extension is provided at bus stops). In the case of offline stops, potential con- flicts arise between buses and bicycles as buses maneuver in and out of the stop, buses must wait for a gap in both bicycle and automobile traffic when exiting the stop, and bicycles can generally continue in a straight line past a stopped bus. In the case of online stops, buses stop in the traffic lane (minimizing bus delays when leaving the stop), while other traffic, including bicycles, must either wait behind the bus or (if possible) pass the bus using the adjacent lane. Shared Bus and Bicycle Lane Shared bus and bicycle lanes (Figure C-1b) have been used where it is desired to benefit both bus and bicycle traffic, but right-of-way constraints prevent developing separate bus and bicycle facilities. Buses travel more quickly than in a mixed-traffic environment, 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 A P P E N D I X C Managing Bus and Bicycle Interactions
168 A Guidebook on Transit-Supportive Roadway Strategies relatively infrequent, help reduce the perception that the lane is not being used efficiently. Buses and bicycles interact similarly to what occurs in shared mixed-use lanes. Separate Bicycle Lane In a separate bicycle lane (Figure C-1c), bicyclists are provided with their own lane, while buses share a lane with general traffic. When the bicycle lane is adjacent to the curb, buses stop in the bicycle lane to serve passengers, which causes bicyclists to wait behind the bus or, more commonly, to go around the bus by merging left into the general traffic lane, thereby creating potential conflicts with other vehicles, including with buses reentering the general traffic lane. When on-street parking is provided to the right of the bicycle lane, buses must weave across the bicycle lane to enter and exit the bus stops created in the parking lane, creating potential conflict points with bicycles, but typically allowing bicyclists to remain in the bicycle facility. When the (a) Shared mixed-use lane (Albuquerque) (b) Shared bus and bicycle lane (Austin) (c) Separate bicycle lane (Washington, D.C.) (d) Separate bus and bicycle lanes (Austin) (e) Left-side bicycle lane (New York) (f) Raised bicycle lane at transit stop (Portland) Figure C-1. Examples of options for accommodating bus and bicycle traffic.
Managing Bus and Bicycle Interactions 169 bicycle lane is located between the curb and a parking lane (e.g., a buffered bicycle lane), it may be possible to raise the bicycle lane to sidewalk level at bus stops (as discussed in the Diverted Bicycle Lane section), eliminating bicycleâvehicle conflicts at bus stops but introducing potential bicycleâpedestrian conflicts. The width used by the parking lane and buffered bicycle lane could also become a shared bus and bicycle lane at the bus stop. Separate Bus and Bicycle Lanes Where right-of-way permits, it may be possible to provide separate bus and bicycle lanes (Figure C-1d). Although buses need to pull into the bicycle lane at bus stops, sufficient space is provided to allow bicycles to go around buses without having to merge into the general traffic lane, reducing the number of conflicts relative to the case where no bus lane is provided, but still forcing bicyclists to maneuver out of their desired travel path. Except when bus volumes are high enough that bicyclists are frequently passed by buses, the bus lane serves as a buffer between bicyclists and motor vehicles. If sufficient space is available, it may be possible to raise the bicycle lane to sidewalk level at bus stops (as discussed in the Diverted Bicycle Lane section), eliminating bicycleâbus conflicts at bus stops but introducing potential bicycleâpedestrian conflicts. Left-Side Bicycle Lane On one-way streets, an additional option for providing separate bus and bicycle lanes is to locate the bus lane on the right side of the street and the bicycle lane on the left side of the street (Figure C-1e). This arrangement eliminates bicycleâbus conflicts at bus stops and can also reduce the dooring risk for bicyclists since passenger-side car doors are opened less frequently than driver-side doors. Additional signs and pavement markings may be required to highlight to motorists where to expect bicyclists (NACTO 2012). Diverted Bicycle Lane at Bus Stops Where space permits, an option for preventing bicycleâvehicle conflicts at bus stops is to divert the bicycle lane around the bus stop, either at its original grade or by raising the bicycle lane to sidewalk level in the vicinity of the bus stop (Figure C-1f). Sufficient space needs to be provided for the ADA-required clear area for bus boarding and alighting, and an ADA-compliant pedestrian access route needs to connect the stop to the sidewalk. Potential bicycleâpedestrian conflicts (e.g., conflicts arising from pedestrians crossing the bicycle lane or queuing in the bicycle lane while waiting for the bus) also need to be addressed. Nevertheless, this treatment can be an effective way to minimize conflicts and delays for both buses and bicyclists. C.3 Implementation Examples There are many implementations of bus-only lanes and bicycle-only lanes around the United States. This section focuses on implementations of the less-common methods of accommodating bus and bicycle traffic that have been identified in the literature. Shared Bus and Bicycle Lane 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;
170 A Guidebook on Transit-Supportive Roadway Strategies Geneva, Switzerland; and Edinburgh and London, United Kingdom. The authors 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 com- muter 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. Left-Side Bicycle Lane New York City implemented left-side bicycle lanes on 1st and 2nd Avenues in Manhattan in conjunction with right-side bus lanes as part of their Select Bus Service program (New York City DOT and MTA-NYCT 2011). Portland, Oregon, uses left-side bicycle lanes on a portion of the 5th Avenue transit mall in conjunction with right-side bus and light rail lanes. Philadelphia (Walnut Street), Chicago (Dearborn Street), and Denver (15th Street) have implemented left-side bicycle lanes on streets with frequent bus service but have not installed bus lanes. NACTO (2012) identifies 11 other cities that have installed left-side bicycle lanes but does not state whether these streets have relatively high bus volumes or whether the lanes were installed for other reasons (e.g., to facilitate bicycle turning movements or to minimize driveway or parking conflicts). Diverted Bicycle Lane at Bus Stops Portland, Oregon, uses raised bicycle lanes at streetcar stops on NW Lovejoy Street and SW 5th Avenue; one reason for installing this treatment was to avoid forcing bicyclists to cross the streetcar tracks twice at a shallow angle when passing stopped streetcars, which entails a risk of having oneâs bicycle wheel get caught in the gap adjacent to the rails. Winnipeg, Canada, installed a raised bicycle lane as a pilot project at a bus stop on Pembina Highway. An evaluation of the design (Suderman and Redmond 2013) found that it generally worked well. Although cyclists usually had to maneuver around pedestrians standing in or crossing the raised portion of the bicycle lane (marked only by a parallel set of bricks creating a stripe effect), they did not have to stop. Snow clearing was a challenge since the snow ridges (windrows) created by snow- plows blocked access from the at-grade bicycle lane to the raised bicycle lane and vice versa. (This is a potential issue at any location where a raised cycle track begins or ends.) Raised cycle tracks are commonly used in Denmark, where the preferred treatment is to divert them around bus stops whenever space permits; otherwise, bicyclists are required to stop for passengers who are boarding from and alighting onto the cycle track (Andersen et al. 2012). (Note the board- ing islands used in Denmark are frequently narrower than what the ADA would permit in the United States.) An at-grade cycle track on Guadalupe Street in Austin, Texas, is diverted at grade around a bus stop at West 21st Street, and examples of diverted bicycle lanes can also be found in Seattle, Washington (e.g., Dexter Avenue). C.4 Existing Implementation Guidance United States AASHTO Transit Design Guide AASHTOâs Transit Guide (2014) acknowledges the potential trade-offs between bus and bicycle facilities in its policy context section (Section 188.8.131.52.3). It notes that bicycles using an exclusive bus lane may sometimes restrict bus speeds to that of bicycles, that bicycleâbus con- flicts may occur at bus stops when a bicycle lane is provided to the right of a bus lane, and that bicycleâbus and bicycleâvehicle conflicts may occur when a bicycle lane is provided between a bus lane and a general traffic lane.
Managing Bus and Bicycle Interactions 171 The guide identifies high bicycle volumes as a condition that would not support installing curb extensions (Section 184.108.40.206.1). The guide notes that if curb extensions are provided, the bicycle facility might need to be routed around the bus stop, which could create bicycleâpedestrian or bicycleâmotor vehicle conflicts. In the section on bus operation in mixed traffic (Section 5.3.1), the guide states that bicycles and buses can share streets that have bicycle lanes, wide curb lanes, or paved shoulders with few or no conflicts. In these cases, âbicycles can maneuver around a stopped bus with little difficulty,â although the difficulty increases as the number of buses increases or bus stop spacing decreases. Bus pullouts are suggested as a means for minimizing bicycleâbus conflicts and allowing bicyclists to remain in their facility at bus stops. The guide states that, due to the increased discomfort caused to bicyclists and bus operators and the reduction in the laneâs operational efficiency, it may not be possible to accommodate shared bus and bicycle traffic on high-speed roadways unless adequately wide bicycle facilities are provided. Finally, the guide identifies 11 ft as the minimum width for a bus lane, with 12 and 13 ft identified as preferable and desirable widths, and states that bus lanes should be wider than these dimensions when shared with bicycles. The guide refers readers to AASHTOâs bicycle guide (2012) for recommended widths for lanes shared by buses and bicycles (Section 220.127.116.11); as noted in the following, the bicycle guide provides general guidance on shared-lane widths but no guidance on shared-lane widths specific to buses. AASHTO Bicycle Design Guide AASHTOâs bicycle guide (2012) includes sections on integrating bicycles with transit (Sec- tion 2.7) and shared lanes (Section 4.3). The guide describes the âleapfrog effectâ as a primary operating issue when bicycles and buses share the same lane, with bicycles passing buses at bus stops and buses then re-passing bicycles on the way to the next stop. However, research for the Florida DOT on shared bus and bicycle lanes (Hillsman et al. 2012) did not find support for the leapfrog effect, except perhaps on one higher-speed roadway that was studied. The Florida report documented that during 36 h of videotaping at three locations by a study in Minneapolis of a shared bus and bicycle lane, 21 passing maneuvers (bicycles passing buses or buses passing bicycles) were observed. The Florida report speculates that bus drivers and bicyclists adjust their speeds to minimize the need to pass. The AASHTO bicycle guide identifies âeffective countermeasuresâ for leapfrogging that include providing âproper pavement markings for bike lanes at bus stops,â left-side bicycle lanes, combined bus and bicycle lanes, extra training for bus drivers, and educational materials for bicyclists (which could possibly be posted on the side or back of a bus). With regard to lane widths for lanes shared by bicycles and motor vehicle traffic in general, the AASHTO bicycle guide identifies 14 ft as the minimum width that allows motorists to safely pass bicyclists without encroaching into the adjacent traffic lane, with the usable lane width measured as either (1) center of edge line to center of lane line or (2) gutter longitudinal joint to center of lane line. AASHTO recommends 15 ft for a shared-lane width on steep grades or when on-street parking or drainage grates reduce the usable lane width. AASHTO cautions that shared-lane widths greater than 16 ft may promote side-by-side automobile driving, increased heavy vehicle use, higher motor vehicle speeds, or a combination of these, and recommends that separate bicycle lanes or facilities be provided when width permits. The AASHTO bicycle guide recommends considering shared-lane markings for bicycles in the following situations related to buses: (1) when lanes are too narrow for side-by-side motor vehicle and bicycle operation and (2) at transit stops to provide guidance to both bicyclists and bus drivers. Shared-lane markings are not recommended when roadway speeds are greater than 35 mph.
172 A Guidebook on Transit-Supportive Roadway Strategies Manual on Uniform Traffic Control Devices The MUTCD (FHWA 2009) provides guidance on signing and marking bus lanes (Sections 2G and 3D, respectively) and on signing and marking bicycle facilities (Sections 9B and 9C, respec- tively) but does not provide guidance on signing shared bus and bicycle lanes. As part of a study for the Florida DOT, Hillsman et al. (2012) asked the FHWA for guidance on signing such lanes and were provided with this guidance: â¢ The lane can be marked and signed for buses and bicycles only (with the option to allow right turns at intersections). In this case, bicycle shared-lane markings (sharrows) should not be used as the lane is designated as an exclusive bicycle facility. â¢ The lane can be marked and signed for buses only (with the option to allow right turns at inter- sections). In this case, bicycle shared-lane markings may be used to indicate that bicycles are allowed to use the lane; this message can be reinforced with a modified R4-11 sign that reads âBikes May Use Bus Lane.â The shared-lane markings may also be used to guide bicyclists to the left side of the lane at bus stops and intersections. â¢ Advisory bicycle lane markingsâdashed lines and bicycle lane signs indicating a reserved space for bicycles that vehicles can enter when necessaryâare a treatment that has been used internationally but would require FHWA experimentation approval for use in the United States. At locations where a bicycle facility is diverted around the bus stop, the âBikes Yield to Pedsâ sign (R9-6) could be used to give priority to persons crossing the bicycle facility to get to or from a boarding island. Americans with Disabilities Act The U.S. Department of Transportation has adopted standards for transportation facilities that implement the requirements of the Americans with Disabilities Act. Section 810 of the standards address bus stops (U.S. Access Board 2006). A relevant provision when considering altering a bus stop to provide a raised bicycle lane is that the bus boarding and alighting area should provide a clear length of 96 in. This suggests that boarding islands would need to provide at least 8 ft of clear space between the outer curb and the bicycle facility, and more if the bicycle facility was at grade and a curb ramp was required to take the accessible route to and from the stop across the bicycle facility. The U.S. Access Boardâs Proposed Guidelines for Pedestrian Facilities in the Public Right-of-Way (2011) repeats the requirement for a clear length of 8 ft (section R308) and adds a new require- ment for detectable warning surfaces (i.e., truncated domes) along the platform edge adjacent to the street. The Access Boardâs discussion (2013) on a proposed supplement to the public right- of-way guidelines for shared-use paths indicates that it is considering including a requirement in the final regulations to provide detectable warning surfaces âwhere a shared use path intersects another shared use path or a sidewalk to indicate the boundaries where bicyclists may be crossing the intersection,â with such surfaces to be installed within 6 to 12 in. of the edge of the intersecting paths and extending â2 feet minimum in the direction of pedestrian travel and the full width of the intersecting segments.â This requirement, if adopted, would likely require detectable warning surfaces on either side of the raised bicycle lane for the length of the boarding island on the side opposite the street. NACTO Urban Bikeway Design Guide The National Association of City Transportation Officialsâ general guidance relating to bicycle facilities in the vicinity of bus stops is that âspecial consideration should be given at transit stops to manage bicycle and pedestrian interactionsâ (NACTO 2012).
Managing Bus and Bicycle Interactions 173 The section of the NACTO guide on one-way protected cycle tracks includes an illustration of a treatment that wraps an at-grade bicycle facility around a bus boarding island. Curb ramps facilitate wheelchair access between the sidewalk and boarding island; crosswalk markings are shown at this crossing point, along with yield symbol markings across the bicycle facility to indicate that bicyclists should yield. The NACTO illustration also shows the potential for pedes- trian access via a ramped walkway, located between the general traffic lane and the bicycle lane, that connects the intersection crosswalk to the boarding island. The section of the NACTO guide on raised cycle tracks indicates the need for âcolor, pavement markings, textured surfaces, landscaping, or other furnishings to discourage pedestrian use of the cycle zoneâ when the cycle track is at sidewalk height. NACTOâs design guidance for cycle tracks on intersection approaches also provides relevant guidance for bus stops: â¢ Use a maximum 1:8 slope (i.e., 12.5%) when lowering a bicycle facility to grade. â¢ Avoid sharp changes in direction. â¢ To improve bicyclist visibility, prohibit parking 30 to 50 ft in advance of an intersection. â¢ When it is possible to install bicycle signals at an intersection, consider raising the cycle track to sidewalk level and wrapping the facility around the bus stop; bicycles would yield to pedestrians in this case. â¢ When bicycle signals are not provided, develop an extended mixing zone at the bus stop. A sign should direct bicyclists to yield to buses and pedestrians. NCHRP Report 672 NCHRP Report 672: Roundabouts: An Informational Guide, 2nd Edition (Rodegerdts et al. 2010) provides guidance in Section 18.104.22.168 on raising bicycle lanes to sidewalk level on an approach to a roundabout; this guidance could also be relevant to raising bicycle lanes at bus stops. The report suggests placing the ramp within the landscaping area, if possible, and orienting the ramp at a 35Â° to 45Â° angle to the sidewalk to slow bicyclists down. Similarly, the report suggests that a grade of up to 20% could be used to slow bicyclists down. At exit points, a shallower ramp angle (e.g., 20Â°) could be used since slowing down bicyclists is not an issue, but âsome angle is necessary so that blind pedestrians do not inadvertently travel down the ramp.â The report also indicates that detectable warning surfaces are required at the top of the ramp to warn visually impaired pedestrians. Finally, bicyclists can be given the option to bypass the ramp (traveling through the roundabout as a vehicle) or to use the ramp (traveling through the roundabout as a pedestrian or shared-use path user). The Netherlands The Design Manual for Bicycle Traffic (CROW 2007) provides some guidance on designing for bicycle and bus interactions. The manual provides minimum widths for the following dimen- sions, among others: shy distance between a bicyclist and a curb (0.25 m) [0.8 ft], width used by an individual bicyclist (0.75 m) [2.5 ft], shy distance between one bicyclist passing another (0.5 m) [1.6 ft], and shy distance between a vehicle and a bicyclist (0.85 m) [2.8 ft]. The manual states that âalmost all motorized traffic will overtake bicycle trafficâ when the available road space accommodates the width of the car plus an 0.85 m or greater separation from the bicyclist. If the available separation is less than 0.85 m, some motorists will try to pass anyway, while others will remain behind the bicyclist, âwhich leads to a dangerous, unwanted situation.â The manual identifies four combinations of roadway functional classifications for motor vehicles (corresponding to local and collector/arterial) and bicycles (main cycle route and other routes).
174 A Guidebook on Transit-Supportive Roadway Strategies The manual recommends separating bicycle and bus traffic on collector/arterial roadways and preferably separating them on local roadways that serve as main cycle routes. No separation is necessary or desirable on local roads that are not main cycle routes. More specifically, the manual recommends separating bus and bicycle traffic when bus speeds exceed 30 km/h (20 mph). The manual states that âcyclists may be permitted to ride on bus lane carriageways if they have their own separate lane,â and that bike lanes should not be placed between the bus lane and a general traffic lane. The minimum recommended width for the combination of a bus-only lane and bicycle lane is 4.60 m (15 ft), increasing to 5.00 m (16.5 ft) if driving speeds exceed 50 km/h (30 mph). The manual recommends that buses stop off the roadway (i.e., in a pullout) when they would otherwise need to stop in a bicycle lane. The conflict involved with crossing the bicycle lane is judged to be ânot serious and hence acceptable.â Pullouts should be designed so that no part of the bus blocks the bicycle lane. When raised cycle tracks are provided, the manual recommends curving them around the bus stop. Denmark The Collection of Cycle Concepts (Andersen et al. 2012) discusses bicycle and bus interactions at bus stops at several points. In terms of bus stop location, in order to avoid bicycleâcar conflicts caused by bicyclists weaving around stopped buses, the guide recommends using bus pullouts when buses would have to stop in a bicycle lane. In this case, the bicycle lane striping should be dashed, and bicycle symbols should be placed at the bicycleâbus conflict points. Alternatively, the bicycle lane can be raised and routed around the bus stop. When bicycle lanes are buffered by a row for parking, the space used for parking can be used for a boarding platform at bus stops. Raised cycle tracks between the travel lane and the sidewalk are a common bicycle facility type in Denmark but have problems in space-constrained locations where bus passengers must board and alight from the cycle track because bicyclists do not always yield to pedestrians as they should. Pedestrian crossing markings on cycle tracks at these locations have been shown to reduce bicycle speeds noticeably but are no longer allowed by Danish road standards (as they lead pedestrians into the street when a bus is not present). A technological solution in which crosswalk markings would be projected onto the cycle track when a bus is present may be tested in the future. The guide recommends setting back bus stops at least 20 m (65 ft) from intersections since stopped buses block motoristsâ views of bicyclists. The guide also recommends never placing bus stops right at the stop bar at intersections because a line of stopped bicyclists can block buses trying to access the stop. According to the guide, far-side stops work best for both buses and bicyclists. C.5 Discussion Overview Managing bicycleâbus interactions at bus stops can result in efficient operations for buses and bicyclists. Redesigning a roadway to provide bus preferential treatments and bicycle accommo- dations can help build support for a bus-focused project by increasing the number of stakeholders benefiting from the project. In jurisdictions requiring bicycle facilities to be incorporated into new or upgraded roadway projects, finding a way to safely accommodate bicycles may influence whether the desired bus preferential treatment can be constructed. In all cases, incorporating bicycle considerations into a project reflects a Complete Streets approach in which a roadway functions well for users of many different travel modes.
Managing Bus and Bicycle Interactions 175 Lane Width There is a consensus in the literature that the width provided to buses and bicycles plays a role in determining how safely the two modes interact as well as the quality of service provided to each mode. In addition, higher motor vehicle speeds and higher bicycle or bus volumes suggest the need for greater separation. Hillsman et al. (2012) calculated the minimum width required for a shared bus and bicycle lane to ensure âsafety and satisfactory level of service for all roadway users.â Their calculated width of 16 ft, 7 in. included 3 ft, 4 in. of bicycle operating space and shy distance to the curb, 3 ft of clearance between a motor vehicle and a bicycle (required by law in Florida and a number of other jurisdictions), 8 ft, 6 in. width for a standard transit bus, and 1 ft, 9 in. clearance to the left edge of the lane (placing the bus within the middle of the leftmost 12 ft of the lane). With this width, buses would not need to move sideways in the lane when passing bicyclists yet an adequate buffer between buses and bicycles would be maintained. Hillsman et al. (2012) also inventoried the actual widths of shared bus and bicycle lanes constructed in the United States, which ranged from 9 to 16 ft, with the width of a number of facilities varying along their length. The total width of constructed adjacent bus and bicycle lanes ranged from 15 to 20 ft. The researchers also inventoried roadway agency standards for shared and adjacent bus and bicycle lanes but found few formal standards. Among the four U.S. cities they identified with standards for shared bus and bicycle lanes, three used 10 ft to either 12 or 13 ft as a standard; the fourth used 12 ft as a minimum width and 18 ft as a preferred width. Two U.S. cities used 14 to 17 ft as the standard for adjacent bus and bicycle lanes. The lower end of these shared bus and bicycle lane widths identified (e.g., 10 to 13 ft) roughly correspond to AASHTOâs (2014) guidance for bus lane widths (11 to 13 ft). A shared bus and bicycle lane with a width under 16 ft would require buses to use the adjacent lane (if available) to pass bicycles. This is based on 1.5-ft curb-and-gutter width, 3-ft minimum bicycle operating space, 3-ft clearance between bus and bicycle, and 8.5-ft bus width. However, as 16 ft also repre- sents the total of AASHTOâs minimum bus lane width (11 ft) and NACTOâs (2012) minimum bicycle lane width (5 ft), providing separate bus and bicycle facilities would seem to be preferable to providing a shared lane of the same width, unless local standards prescribed wider minimum widths (e.g., 12-ft bus lanes or 6-ft bicycle lanes). A bicycle passing a stopped bus would require a minimum of 14.5 ft of width to avoid entering the adjacent lane (8.5-ft bus width, 3-ft clearance, 3-ft bicycle operating space). Shared Versus Adjacent Bus and Bicycle Lanes AASHTO (2014) does not provide minimum bus volumes for installing a bus lane but notes that âpeak hour one-way bus volumes of about 40 to 75 buses will provide a bus presence without creating excessive bunches.â NACTOâs (2012) guidance 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 or greater. Based on the NACTO 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, unless it is possible to route bicycles around bus stops, short sections of a shared lane without bus stops would operate better for both buses and bicycles compared to frequently spaced stops across longer sections.
176 A Guidebook on Transit-Supportive Roadway Strategies Roadways with significant uphill grades would not be good candidates for relatively narrow shared lanes because the speed differential between bicycles and buses would be considerably greater, and buses would experience greater delay in situations where they could not imme- diately pass bicyclists compared to level or downhill roadway sections. 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 bicyclist and because bicyclists must pass stopped buses. Buffered bicycle lanes or raised cycle tracks are potential solutions when it is desired to main- tain on-street parking. The parking lane would be placed between the bicycle lane and the bus lane and would be replaced with a boarding island at bus stops. Bicycleâbus conflicts would be eliminated, potential conflicts between car doors and bicycles would be reduced, and bicyclists would be buffered from moving motor vehicle traffic. Managing BicycleâBus Conflicts at Bus Stops Diverted Bicycle Lane at Bus Stops Where space permits, a diverted bicycle lane is an option for midblock and far-side bus stops for managing bicycleâbus conflicts. (They are more challenging to install at near-side stops at the intersection since there is typically insufficient length available to transition the bicycle facil- ity back into the street, and pedestrianâbicycle interactions at street corners have to be carefully managed.) The required space could be created from space used for landscaping or street furni- ture elsewhere along the block face or from the space used by on-street parking. A minimum of 8 ft of width would be required between the curb and the bicycle lane to meet ADA standards (at least at the location where the ADA pedestrian access route to and from the bus stop would cross the bicycle lane). More width may be required if (1) the bicycle lane is at a lower grade than the bus stop platform, thus requiring curb ramps at the point the pedestrian access route crosses the bicycle lane, or (2) the number of waiting passengers that need to be accommodated on the bus stop platform creates the need for more waiting area. The Transit Capacity and Quality of Service Manual (Kittelson & Associates et al. 2013) provides methods for estimating the required platform area given the number of passengers to be designed for. San Franciscoâs accessible bicycle facility guidelines (SFMTA 2014) provide an example of raising the bicycle lane to the platform grade at the location of the ADA pedestrian access route. The literature generally agrees that it is necessary to manage bicycleâpedestrian conflicts when diverted bicycle lanes are used at bus stops, but it does not agree on the methods that should be used. European practice and NACTO suggest a shallower angle and, when the bicycle lane is raised, gentler slopes when diverting a bicycle facility around a bus stop; this approach allows bicyclists to maintain their speeds since conflicts may be minimal whenever buses are not actively loading and unloading passengers. A Canadian implementation and U.S. round- about practice suggest a sharper angle and a steeper slope to force bicyclists to slow down. The Canadian implementation (Suderman and Redmond 2013) used a 20Â° angle and a 5% slope, narrowed the bicycle facility from approximately 6 ft to approximately 4 ft, and introduced a rumble strip on the bicycle facility. The MUTCD provides or is expected to provide in the next edition guidance on colored pavement, bicycle markings, and âBikes Yield to Pedsâ signs. Con- flicts may arise between bicyclists and sight-impaired pedestrians who cannot see or hear bicy- clists approaching, and in the future, regulations implementing the ADA may require detectable warning surfaces separating the bicycle facility from both the sidewalk and the bus stop. Clearly there is an opportunity for more research on the design of diverted bicycle lanes at bus stops; ultimately, the design selected may depend on the relative volumes of buses, bicycles, and passengers using the stop, bus and general traffic speeds, and the design of the bicycle facility
Managing Bus and Bicycle Interactions 177 (i.e., shared, adjacent to the travel lane, or buffered). If the number of buses using the stop is relatively low, bicyclists could ride through the bus stop most of the time since no buses would be present. However, as the number of buses stopping increases and the number of passengers boarding or alighting a given bus increases (thus increasing bus dwell time), the probability that a bus will interfere with a bicyclist will increase, and the benefit of separating bicyclists from buses will also increase. The leftmost diagram in Figure C-2 uses elements identified in the literature to illustrate a design concept for a bus stop with a raised bicycle lane. (All of the diagrams in Figure C-2 illustrate only the portion of the street serving one direction of travel. For ease of presenting the basic design elements, a midblock stop is depicted.) In this concept, the basic street cross-section includes a 6-ft bicycle lane and a 6-ft landscape buffer. At the bus stop, the bicycle lane is diverted out of the street at a 20Â° angle, raised to sidewalk level, and narrowed to 4 ft wide, leaving 8 ft of width for the boarding area. A âBikes Yield to Pedsâ sign is provided near the start of the ramp. Paint or contrasting pavement color is used to designate the bicycle lane. After the stop, the bicycle lane is lowered and angled back to its original alignment. Not shown, but potentially required, are detectable warning surfaces along the edge of the raised bicycle lane. A rumble-strip treatment could also be considered to encourage bicyclists to slow down, but potential pedestrian tripping hazards would need to be addressed. Local laws that prohibit bicycling on sidewalks might require changing to allow a raised bicycle lane configuration. An at-grade diverted bicycle lane would be developed similarly but without the changes in bicycle lane grade. The bicycle lane width would need to be wider (e.g., 5 ft) than in the raised case to accommodate shy distance from both curbs, particularly for cargo bicycles and bicycles with trailers. Additional boarding platform width might be required to accommodate curb ramps at the point the pedestrian access route crosses the bicycle lane. ONLY BUS BU S RAISED BIKE LANE BU S EXCLUSIVE BUS AND BIKE LANES BU S LEFT-SIDE BIKE LANE ONLY BUS BU S SHARED BUS AND BIKE LANE ONLY BUS BU S EXCLUSIVE BIKE LANE ONLY BUS BUS BUS Travel lanes Bike lane Sidewalk and Buffer Travel lane Bike lane Side- walk Bus lane Bike lane Travel lanes Side- walk Park- ing Travel lane Bus/bike lane Side- walk Travel lanes Bike lane Side- walk Bus stop sign Bus stop sign Bus stop sign Bus stop sign Bus stop sign Figure C-2. Illustrative design concepts for accommodating bus and bicycle traffic.
178 A Guidebook on Transit-Supportive Roadway Strategies Exclusive Bus and Bicycle Lanes When space does not permit detouring a bicycle facility around a bus stop, and a bus lane is desired on the street, another option for two-way streets, if sufficient space exists for both facili- ties, is to provide separate bus and bicycle lanes. This arrangement allows buses to pass bicyclists between bus stops and provides sufficient room for bicyclists to pass stopped buses without having to use a general travel lane. Bicycleâvehicle interactions are limited to buses, which are driven by professional drivers. The second-to-the-left diagram in Figure C-2 draws from the literature to illustrate a concept for the basic signing and marking features in the vicinity of a bus stop. The bicycle lane marking becomes dotted at the point where a bus would pull over to the curb in advance of the bus stop and remains dotted beyond the stop to a point where a bus would have fully reentered the travel lane (see Figure 9C-6 in the MUTCD for an illustration of bike lane markings near bus stops). A âBikes May Use Bus Laneâ (modified R4-11) sign is placed at the point where buses may enter the bicycle lane. (Local or state traffic laws may need to be updated to allow bicycles to use bus lanes in this manner.) Shared-lane markings (sharrows) are placed at the outside of the exclusive bus lane to indicate to bicyclists where to travel when the bus stop is in use. (This use assumes that the speed limit is 35 mph or less, per MUTCD requirements.) Installing a concrete pad at the bus stop can minimize bus-caused pavement deformation that could negatively affect bicyclists. Left-Side Bicycle Lanes The literature is in general agreement that left-side bicycle lanes are a potential treatment for one-way streets since they can provide benefits to buses and bicyclists. Motoristsâ attention may need to be drawn to the presence of bicyclists on the left side because motorists may not be accustomed to looking for bicyclists there; NACTO (2012) provides guidance on signing and marking left-side bicycle lanes. The middle diagram in Figure C-2 shows a concept for a one-way street that allows on-street parking on the right side and provides a left-side bicycle lane (which could possibly have on-street parking to its left). The space used by the parking lane is used for a curb extension at the bus stop, allowing buses to stop in the travel lane (reducing bus delay) and providing a waiting area for passengers without disrupting pedestrian flow on the adjacent sidewalk. Shared Bus and Bicycle Lanes Where space does not permit providing separate bus and bicycle lanes, and a bus lane is desired to improve bus operations, shared bus and bicycle lanes can be considered. Although the operation of buses and bicycles passing each other still needs to be consideredâparticularly at bus stopsâa Florida study (Hillsman et al. 2012) did not find support for the âleapfroggingâ phenomenon raised by AASHTO (2014) as a potential issue. Research is needed in this area. Bicyclists and buses benefit from the reduced amount of traffic using a shared bus and bicycle lane. Wider lanes minimize the need to encroach into the adjacent travel lane when passing. The second-to-the-right diagram in Figure C-2 draws from the literature to show a concept for a shared bus and bicycle lane in the vicinity of a bus stop. In this concept, the lane is marked as a bus lane, and periodic âBikes May Use Bus Laneâ (modified R4-11) signs are used to indicate that bicycles may also use the lane. (Local or state traffic laws may need to be updated to allow bicycles to use bus lanes in this manner.) To help guide bicyclists with their placement within the lane, shared-lane markings (sharrows) are placed on the right side of the lane between bus stops and on the left side of the lane immediately prior to a bus stop. (Again, this use assumes that the posted speed is 35 mph or less, per MUTCD requirements.) Installing a concrete pad at the bus stop can minimize bus-caused pavement deformation that could negatively affect bicyclists.
Managing Bus and Bicycle Interactions 179 Exclusive Bicycle Lanes Providing an exclusive bicycle lane rather than a shared mixed-use lane avoids the need for buses to change lanes when passing a bicyclist, thus reducing bus delay on streets used by significant numbers of bicyclists. At the same time, bicyclists benefit from the separation from general traffic. The rightmost diagram in Figure C-2 draws from the literature to show a concept for an exclu- sive bus lane in the vicinity of a bus stop. Similar to the case of separate exclusive bus and bicycle lanes discussed earlier, the bicycle lane marking becomes dotted at the point where a bus would pull over to the curb in advance of the bus stop and remains dotted beyond the stop to a point where a bus would have fully reentered the travel lane (see Figure 9C-6 in the MUTCD for an illustration of bike lane markings near bus stops). If the streetâs posted speed is 35 mph or less, shared-lane markings (sharrows) are placed sufficiently far into the adjacent lane in the vicinity of the bus stop that bicyclists have a 3-ft buffer to a stopped bus. A âBicycle Warningâ (W11-1) sign with a âShare the Roadâ plaque (W16-1P) is installed in advance of the end of the exclusive bicycle lane. The MUTCD states (Section 9B.19.03) that this plaque should be installed at least 50 ft in advance of the condition being warned about; general MUTCD guidance for warning signs (Table 2C-4) would indicate a maximum distance of 100 ft, with consideration given to site conditions and the location of other signs. Installing a concrete pad at the bus stop can minimize bus-caused pavement deformation that could negatively affect bicyclists. Shared Mixed-Use Lanes If the roadway is designated as a bicycle route or if the combination of bus and bicycle volumes and dwell times (e.g., a timepoint, a high-volume stop) are high enough that stopped buses would often be passed by bicycles, then a âBikes May Use Full Laneâ (R4-11) or a âBicycle Warningâ (W11-1) sign with a âShare the Roadâ (W16-1P) plaque could be considered at bus stops along that roadway. If the lane is sufficiently wide and posted speeds are 35 mph or less, then shared-lane markings (sharrows) could also be considered. Bus Pullouts Bus pullouts, or bus bays, are not generally desirable from a bus operations standpoint due to the delays buses encounter waiting for a gap in traffic when leaving the pullout. However, they are sometimes needed to reduce the risks of vehicle conflictsâfor example, when buses operate on higher-speed roadways (e.g., greater than 40 mph) or due to traffic operations considerations such as the number of vehicles that might be delayed, the length of time they might be delayed, and inability for vehicles to pass a stopped bus (AASHTO 2014). If a pullout is required, it should allow a bus to stop without blocking the adjacent bicycle lane or shoulder bikeway (if present). If a bicycle lane exists, the lane lines would be dotted in the vicinity of the bus stop to indicate that buses can pass through the lane while entering and exiting the stop. When sufficient right-of-way exists to install a pullout, there may be benefit to routing a bicycle facility (if present) around the pullout to avoid bicycleâbus conflicts when buses are entering and exiting the stop. C.6 Conclusions Additional research is needed to better quantify the operational and safety performance of buses, bicycles, and other roadway users associated with the different types of bus stop treat- ments. In the absence of this research, the literature suggests the following order of preference for accommodating both buses and bicycles at bus stops: 1. Providing a left-side bicycle lane on one-way streets, separating bus and bicycle traffic entirely, with consideration given to calling motoristsâ attention to the presence of bicyclists, who could be in an unexpected location.
180 A Guidebook on Transit-Supportive Roadway Strategies 2. Diverting the bicycle facility around the bus stop, with consideration given to managing bicycleâpedestrian conflicts at the stop. 3. Providing separate exclusive bus and bicycle lanes, which eliminates the need for busâbicycle passing maneuvers between stops and provides sufficient room for bicycles to pass buses at bus stops without having to move into the adjacent general traffic lane. 4. Providing a shared bus and bicycle lane, with wider lanes functioning best. A 16-ft width allows buses to pass bicycles without encroaching on 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 on the adjacent lane. However, widths down to 11 ft (i.e., the minimum recommended bus lane width) still provide better separation between bicycles and general traffic than occurs in a mixed-traffic environment and may be appropriate in situations where bus volumes are relatively low (e.g., less than 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. Depending on the volume of bicycles sharing the lane and the width of the lane, buses can retain much of the benefit of having an exclusive bus lane, while bicyclists have a wider buffer between themselves and general traffic than with an exclusive bicycle lane or a mixed-traffic environment. Shared bus and bicycle lanes may also be useful in short, space-constrained sections of roadway without bus stops. 5. Providing an exclusive bicycle lane, with buses operating in mixed traffic. Buses avoid the need to pass bicyclists midblock, while bicyclists are generally separated from general traffic, except when they need to pass buses that are stopped at bus stops. 6. Shared mixed-use lanes using shared-lane markings (sharrows) to guide bicyclists around stopped buses at bus stops and to inform motorists to watch for bicyclists. The choice of treatment will depend on a number of factors, including right-of-way availability, bus and bicycle volumes, traffic speeds, the type of existing and planned bicycle facility on the roadway, existing traffic laws, applicable local roadway design standards, and available budget. Higher bus volumes and the presence of premium transit services (e.g., bus rapid transit) suggest the need for greater separation of bus traffic from other roadway users, while higher bicycle vol- umes or the designation of the roadway as a priority bicycle facility suggest the need for greater separation of bicycle traffic from other roadway users. Bus pullouts are not generally desirable from a bus delay standpoint, but when they are used (e.g., on high-speed roadways or as a result of other safety concerns), they should allow buses to stop without blocking the adjacent bicycle lane or shoulder bikeway (if present). Installing a concrete pad at the bus stop can minimize bus-caused pavement deformation that could negatively affect bicyclists.