Design Guidance for Channelized Right-Turn Lanes (2014)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Chapter 7. Conclusions and Recommendations This chapter presents the conclusions and recommendations based on the results of the research. Conclusions 7.1 The following conclusions are based on field observational studies of vehicle and pedestrian interactions at channelized right-turn lanes, interviews with orientation and mobility (O&M) specialists, traffic operational analyses of channelized right-turn lanes conducted with VISSIM, and safety analyses of channelized right-turn lanes: • A majority of the sites (nearly 70 percent) had marked crosswalks located near the center of the channelized right-turn lane; only about 30 percent of crosswalks were located at the upstream or downstream end of the channelized right-turn lane. The highway agency survey conducted in NCHRP Project 3-72 (3) found that highway agencies prefer a crosswalk location near the center of a channelized right-turn lane; over 70 percent of highway agencies reported in the survey that their practice was to place crosswalks near the center of channelized right-turn lanes. • Pedestrians did not appear to have any particular difficulty crossing channelized right- turn lanes. Most pedestrians crossed in the crosswalk (75 percent) and, where pedestrian signals were present, most pedestrians crossed during the pedestrian crossing phase (72 percent). The pedestrians who crossed outside the crosswalk generally did so when no vehicular traffic was present and this behavior did not cause any traffic conflicts. Avoidance maneuvers by a pedestrian or motorist appear to be relatively rare, and were observed in less than 1 percent of the pedestrian crossings. • Nearly all motorists (over 96 percent) yielded to pedestrians in the crosswalk, or were unaffected by the pedestrian crossing (i.e., the pedestrian crossed without substantially impacting the vehicle’s speed). The observed yield rate was somewhat lower (approximately 40 percent) for pedestrians waiting at the curb. The failure of vehicles to yield to pedestrians waiting to cross at a marked crosswalk is not unique to channelized right-turn lanes, but is a general problem at pedestrian crosswalks. The yield behavior of motorists was slightly better (47 percent vs. 40 percent) at sites with special crosswalk treatments (e.g., raised crosswalk, pavement markings, signing). This may indicate that additional emphasis on signing or other treatments may be needed to increase yielding for pedestrians waiting at the curb. • There has been little research that evaluates how the crosswalk location affects crossings by pedestrians with vision impairment in terms of their ability to identify the appropriate time to cross of efficiently locate the crosswalk. O&M specialists recommend that consistency of crosswalk location and traffic control is important to pedestrians with vision impairment. They also have a strong preference for raised islands with “cut- 100

through” pedestrian paths, which provide better guidance and information for pedestrians with vision impairment than do painted islands. • Channelized right-turn lanes with yield control were shown to reduce right-turn delay to vehicles by 25 to 75 percent in comparison to intersection approaches with conventional right-turn lanes. High pedestrian volumes increase right-turn delay by approximately 60 percent on a yield-controlled channelized right-turn lane. • The addition of an acceleration lane at the downstream end of a channelized right-turn lane can substantially reduce the right-turn delay (by 65 to 85 percent) depending on the conflicting traffic volume on the cross street. However, channelized right-turn lanes with acceleration lanes appear to be very difficult for pedestrians with vision impairment to cross due to vehicle speeds and lack of yielding by motorists. • Increasing the radius of a channelized right-turn roadway can reduce right-turn delay by approximately 10 to 20 percent for each 8-km/h (5-mi/h) increase in turning speed. However, in previous research (15), higher speeds have been shown to result in a decrease in yielding to pedestrians by motorists. • For channelized right-turn lanes with signal control, use of an overlap phase, or other method of providing additional green time to right-turning vehicles, can substantially reduce the delay for a signalized channelized right-turn lane. However, this may result in other impacts to intersection operations, such as restricting U-turn maneuvers. • Intersection approaches with channelized right-turn lanes appear to have similar motor- vehicle safety performance as approaches with conventional right-turn lanes or shared through/right-turn lanes. This was found to be the case both at the downstream end of the channelized right-turn lane (where the right-turning vehicle merges with the cross street) as well as at the upstream end of the channelized right-turn lane (where the right- turning vehicle begins the right-turn maneuver). • Intersection approaches with channelized right-turn lanes appear to have similar pedestrian safety performance as approaches with shared through/right-turn lanes. Intersection approaches with conventional right-turn lanes have substantially more pedestrian crashes (approximately 70 to 80 percent more) than approaches with channelized right-turn lanes or shared/through right-turn lanes. Recommendations 7.2 The following recommendations were developed in the research: • Channelized right-turn lanes have a definite role in improving operations and safety at intersections. However, to achieve these benefits, they should have consistent design and traffic control and should be used at appropriate locations. • There has been little research that evaluates how the crosswalk location affects crossings by pedestrians with vision impairment, and more research would be desirable to provide more concrete recommendations. 101

• Since consistency in locating crosswalks is important and since current practice shows a clear preference for crosswalk locations near the center of a channelized right-turn lane, design guidance should recommend placing crosswalks near the center of the channelized right-turn lane for channelized right-turn lanes with yield control or no control at the entry to the cross street. • Where the channelized right-turn lane has STOP sign control or traffic signal control, the crosswalk should be placed immediately downstream of the stop bar. If the channelized right-turn roadway intersects with the cross street at nearly a right angle, the stop bar and crosswalk can be placed at the downstream end of the channelized right-turn roadway. • Raised islands should be considered because they serve as a refuge area so that pedestrians may cross the street in two stages. Raised islands with “cut-through” also provide better guidance for pedestrians with vision impairment than painted islands. • Channelized right-turn lanes with acceleration lanes appear to be very difficult for pedestrians with vision impairment to cross. Therefore, the use of acceleration lanes at the downstream end of a channelized right-turn lane should generally be reserved for locations where no pedestrians or very few pedestrians are present. Typically, these would be locations without sidewalks or pedestrian crossings; at such locations, the reduction in vehicle delay resulting from addition of an acceleration lane becomes very desirable. • Where a signal is provided for pedestrians to cross a channelized right-turn lane, a pedestrian-actuated signal should be considered. This can reduce vehicle delay because the phase for crossing the channelized right-turn lane is called only when pedestrians are present. • Use of an overlap phase (or other method of providing additional green time to right- turning vehicles) should be considered as it can substantially reduce delay at channelized right-turn lanes with signals tied to the signal cycle of the primary intersection. However, consideration should be given to other possible impacts to intersection operations, such as restricting U-turn maneuvers. The general highway agency practice of using channelized right-turn lanes at intersections with lower pedestrian volumes suggests that this is a reasonable approach, and that caution should be exercised in using channelized right-turn lanes where pedestrian crossing volumes are high (e.g., over 1,000 pedestrians per day). This guidance is based on the 85th percentile pedestrian volume—1,000 pedestrians per day—in the Toronto intersection database that was used for the safety evaluation. While channelized right-turn lanes may be suitable for higher pedestrian volumes, the research cannot predict the safety performance of channelized right-turn lanes with pedestrian volumes beyond the range evaluated in the research. 102