Traffic Signal Control Strategies for Pedestrians and Bicyclists (2022) / Chapter Skim
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Pages 131-159
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From page 131... ...
131 This chapter describes six treatments that address needs specific to bicyclists: C H A P T E R 9 Treatments Addressing Special Bicycle Needs Primary Function Section Treatment Name Improve bicycle safety by providing sufficient clearance time 9.1 Minimum Green and Change Interval Settings for Bicycle Clearance Reduce bicycle delay by providing enhanced progression 9.2 Signal Progression for Bicycles 9.3 Two-Stage Left-Turn Progression for Bicycles Offer signal timing techniques made possible by bicycle detection 9.4 Bicycle Detection Provide information to increase cyclist compliance 9.5 Bicycle Wait Countdown Reduce bicycle delay 9.6 Easing Bicycle Right Turn on Red Restrictions Minimum Green and Change Interval Settings for Bicycle Clearance (Section 9.1) addresses critical timing settings for vehicular phases to ensure that cyclists have sufficient clearance time at the end of a phase.
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132 Traffic Signal Control Strategies for Pedestrians and Bicyclists 9.1 Minimum Green and Change Interval Settings for Bicycle Clearance 9.1.1 Basic Description 9.1.1.1 Alternative Names Bike minimum green; bicycle red clearance interval; bicycle yellow change interval; green extension for bike clearance. 9.1.1.2 Description and Objective The objective is to ensure that bicyclists crossing a street have sufficient time to clear the intersection.
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From page 133... ...
Treatments Addressing Special Bicycle Needs 133 Bicycle detectors have been used in some locations in California to apply bicycle minimum green only when a bike is detected by using the stop-line detector in the bike lane that is already present for call detection. Bike red clearance is rarely applied in the U.S.
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134 Traffic Signal Control Strategies for Pedestrians and Bicyclists where BikeMinGreen = bike minimum green (s) ; Y = yellow time (s)
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Treatments Addressing Special Bicycle Needs 135 treaction = 1.0 s; d = 10 ft/s2 (as suggested in Ontario's bicycle traffic signals manual) ; PET = 1.0 s; and tentry = 2.8 s.
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From page 136... ...
136 Traffic Signal Control Strategies for Pedestrians and Bicyclists provided every cycle; alternatively, minimum green can be provided only in cycles in which a bicycle is detected during the red interval and red clearance can be provided in the last few seconds of green or the first few seconds of yellow. If the extra time needed for bikes is large, bike actuation can allow signal cycles to be more efficient.
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Treatments Addressing Special Bicycle Needs 137 increasing a side street's green duration -- for example, from 6 to 10 s -- will have a negligible effect on average delay. Using microsimulation, Shladover et al.
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138 Traffic Signal Control Strategies for Pedestrians and Bicyclists 9.1.3.3 Relationships to Relevant Treatments Bicycle detection (see Section 9.4) can improve the efficiency of this treatment, particularly for providing bike red clearance at long crossings.
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Treatments Addressing Special Bicycle Needs 139 Curtis, E
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140 Traffic Signal Control Strategies for Pedestrians and Bicyclists On two-way streets, one-way coordination can be applied to a favored direction, which can switch by time of day; the other direction usually gets poor progression as a result (e.g., bicycles can typically get through only a few intersections before they get a red)
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From page 141... ...
Treatments Addressing Special Bicycle Needs 141 only reduces bicycle delay but also improves safety by e ectively limiting motor vehicle speed to 18 km/h, removing the incentive for motor vehicles to pass bicycles. Copenhagen and Utrecht, Netherlands, have installed pilot projects that provide cyclists with advice on whether to speed up or slow down to make the next green phase.
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From page 142... ...
142 Traffic Signal Control Strategies for Pedestrians and Bicyclists For vehicles as well as bicycles, the "ideal" progression speed is 13.5 mph (calculated using the same formula as Equation 9-9) ; this means that if signals were timed for a speed better suited to vehicles -- for example, 25 or 27 mph -- coordination would not be ideal and vehicles would still have to stop frequently, except during light traffic conditions.
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Treatments Addressing Special Bicycle Needs 143 Lower progression speeds in combination with short cycle lengths (see Section 7.1) reduce speeding opportunities, thereby reducing extreme speeds, especially during periods of low traffic (Furth et al., 2018)
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144 Traffic Signal Control Strategies for Pedestrians and Bicyclists 9.2.3.3 Relationships to Relevant Treatments Bicycle coordination should be considered in combination with treatments that substantially reduce bicycle green time to eliminate turn conflicts (e.g., protected-concurrent crossings) and reduce bicycle delay.
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Treatments Addressing Special Bicycle Needs 145 9.3.1.2 Description and Objective To turn le at an intersection, bicyclists have the choice of making a vehicle-style turn, which typically involves shared use of a vehicular le -turn lane, or making a pedestrian-style turn, executed as a pair of simple crossings. In Exhibit 9-3, a northbound le (NBL)
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Exhibit 9-4. Lead-lag progression for bicycles traveling from O Street to D Street.
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Treatments Addressing Special Bicycle Needs 147 bicycle left turns, as every left turn becomes possible by first crossing with the east–west street and then finishing with the north–south street. Left-turning bicyclists approaching the intersection at Crossings A and C can make their left turn by traveling counterclockwise (following the green arrows)
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148 Traffic Signal Control Strategies for Pedestrians and Bicyclists Changing phase sequence to improve bicycle turn progression will have no impact on traffic operations at many intersections, while at others it may affect arterial progression and thereby increase auto delay. 9.3.3 Considerations 9.3.3.1 Accessibility Considerations Not applicable for this treatment.
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Treatments Addressing Special Bicycle Needs 149 9.4 Bicycle Detection 9.4.1 Basic Description 9.4.1.1 Alternative Names Bicycle actuation. 9.4.1.2 Description and Objective In bicycle detection, the presence of bicyclists is made known to the signal controller, which can use that information to activate the signal for phases that serve bikes, including calling for service (see Section 7.5)
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150 Traf c Signal Control Strategies for Pedestrians and Bicyclists 9.4.2 Applications and Expected Outcomes 9.4.2.1 National and International Use Using bicycle-sensitive call detectors for phases shared by bicycles and autos is common in the United States. Where bikes share a lane with motor tra c, a special loop layout resembling a gure eight is used to increase a detector's sensitivity to the relatively small amount of metal in a bicycle.
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Treatments Addressing Special Bicycle Needs 151 at an intersection. At the same time, controller logic has been modi ed to use this information to more quickly change phases in favor of bikes and to extend bike phases (Wagenbuur, 2018)
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152 Traffic Signal Control Strategies for Pedestrians and Bicyclists 9.4.3.2 Guidance Not applicable for this treatment. 9.4.3.3 Relationships to Relevant Treatments Pedestrian recall versus actuation (see Section 7.5)
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Treatments Addressing Special Bicycle Needs 153 Manual on Uniform Tra c Control Devices for Streets and Highways.
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154 Traf c Signal Control Strategies for Pedestrians and Bicyclists 9.5.1.4 Operating Context Bicycle wait countdown signals may be an appropriate treatment for bicycle signals when there is a desire to increase cyclist compliance with the red signals. 9.5.2 Applications and Expected Outcomes 9.5.2.1 National and International Use Amsterdam introduced wait signals in order to reduce noncompliance with red signals.
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Treatments Addressing Special Bicycle Needs 155 9.5.3.2 Guidance Not applicable for this treatment. 9.5.3.3 Relationships to Relevant Treatments Not applicable for this treatment.
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156 Traf c Signal Control Strategies for Pedestrians and Bicyclists 9.6.1.2 Description and Objective is treatment encompasses two provisions that can be applied independently. One is exempting bicycles from no turn on red (NTOR)
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Treatments Addressing Special Bicycle Needs 157 where bicycles are already allowed -- by existing laws -- to turn right on red, or it could be applied universally, in which case it would encompass a universal exemption to NTOR restrictions. 9.6.2 Applications and Expected Outcomes 9.6.2.1 National and International Use In the U.S., bicyclists routinely violate RTOR restrictions.
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158 Traffic Signal Control Strategies for Pedestrians and Bicyclists lanes) -- is that the stop line for bicycles is at the curb of the cross street, so that bicyclists turning right from one cycle track to another never pass the stop line and therefore are not regulated by the traffic signal.
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Treatments Addressing Special Bicycle Needs 159 9.6.4.4 Geometric Elements Not applicable for this treatment. Bibliography Caldwell, J., O'Neil, R., Schwieterman, J
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