U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|This report is an archived publication and may contain dated technical, contact, and link information|
Publication Number: FHWA-HRT-11-039
Date: April 2011
Evaluation of Pedestrian and Bicycle Engineering Countermeasures: Rectangular Rapid-Flashing Beacons, HAWKs, Sharrows, Crosswalk Markings, and the Development of an Evaluation Methods Report
CHAPTER 8. SUMMARY
The overall goal of the FHWA Pedestrian and Bicycle Safety Research Program is to increase pedestrian and bicycle safety and mobility. From improved crosswalks, sidewalks, and pedestrian technologies to educational and safety programs, the program strives to make it safer and easier for pedestrians, bicyclists, and motorists to share roadways. This report documents an FHWA project to quantify the effectiveness of engineering countermeasures in improving safety and operations for pedestrians and bicyclists. The project focused on existing and new engineering countermeasures for pedestrians and bicyclists that have not yet been comprehensively evaluated in terms of effectiveness. The following sections summarize the methodologies used in this project as well as the findings.
The process of identifying potential countermeasures began with an extensive literature review of bicycle and pedestrian countermeasure evaluations. The experimental requests sent to FHWA for bicycle- and pedestrian-related traffic control devices not specifically addressed by the 2009 MUTCD were also summarized. Based on these evaluations, five candidate bicycle countermeasures and nine candidate pedestrian countermeasures were identified and then reviewed by a panel of practitioners. The final selection of the countermeasures to be evaluated considered the following:
The development of an evaluation methods report for pedestrian and bicycle traffic control devices was also included in the project. The purpose of the evaluation methods report is to educate practicing engineers, planners, and public works employees at the local, county, and State level as to how to conduct an evaluation of traffic control device effectiveness.
The RRFB is a pedestrian-activated beacon system located at the roadside below pedestrian crosswalk signs. This study examined the effects of RRFBs at uncontrolled marked crosswalks. Several methods have been examined to increase driver yielding to pedestrians at multilane crosswalks at uncontrolled locations with relatively high ADT. Previously, only treatments that employed a red phase have consistently produced sustained high levels of yielding at high-volume multilane crosswalks. Five experiments examined the efficacy of RRFBs. These studies found that RRFBs produced an increase in yielding behavior at all 22 sites located in 3 cities in the United States. Data collected over a 2-year follow-up period at 18 of these sites also documented the long-term maintenance of yielding behavior produced by RRFBs. A comparison of RRFBs to a traditional overhead yellow flashing beacon and a side-mounted traditional yellow flashing beacon documented higher driver yielding associated with RRFBs that was both statistically significant and practically important. Data from other experiments demonstrated that mounting additional beacons on pedestrian refuge islands, or medians, and aiming the beacons to maximize its salience at the dilemma zone increased the efficiencies of the system. Two other variants were found to not influence the effectiveness of the system.
The HAWK is a pedestrian-activated beacon located on the roadside and on mast arms over the major approaches to an intersection. It was created in Tucson, AZ, and it was used at more than 60 locations throughout the city at the time of this study. The HAWK head consists of two red lenses over a single yellow lens. It displays a red indication to drivers when activated, which creates a gap for pedestrians to use to cross the major roadway. A before-after study of the safety performance of the HAWK was conducted. The before-after evaluation used an EB method to compare the observed crash frequency during the after period (with the treatment installed) to an estimate of what the crash frequency during the after period would have been if the treatment had not been applied. To develop the datasets used in this evaluation, crashes were counted if they occurred within the study period, typically 3 years before HAWK installation and 3 years after HAWK installation or up to the limit of the available crash data for the after period. Two crash datasets were created. The first dataset included ISN crashes, which were all crashes with the same ISNs that matched the intersections used in the study. The second dataset included IR crashes, which were only those ISN crashes that had "yes" for the IR code. The crash types that were examined included total, severe, and pedestrian crashes. From the evaluation that considered data for 21 HAWK sites (treatment sites) and 102 unsignalized intersections (reference group 2), the following changes in crashes were found after the HAWK was installed:
Shared lane markings are intended to inform motorists and bicyclists that they must share the travel way on which they are operating. The purpose of the markings is to create improved conditions for bicyclists by clarifying where they are expected to ride and to notify motorists to expect bicyclists on the road. The purpose of this study was to evaluate the impact of several uses of shared lane pavement markings, specifically the sharrow design, on operational and safety measures for bicyclists and motorists. Experiments were conducted in three cities. In Cambridge, MA, there was interest in experimenting with the placement of sharrows at a 10-ft spacing from the curb to prevent dooring from parked vehicles. In Chapel Hill, NC, sharrows were placed on a busy five-lane corridor with wide outside lanes and no parking. In Seattle, WA, sharrows were placed in the center of the lane on a downhill portion of a busy bicycle commuting street. Prior to the sharrows, a 5-ft bicycle lane was added to the uphill portion of the street in conjunction with shifting the center line of the street. A variety of hypotheses were examined, and a number of variables related to the interaction and spacing of bicycles and motor vehicles showed positive effects. Sharrows can be used in a variety of situations, and it is assumed that increased use should increase motorist awareness of bicycles, or the possibility of bicycles, in the traffic stream. As communities continue to experiment with various uses of sharrows, it is recommended that researchers continue to create similar trials in other locations and traffic settings. Additionally, it is important to evaluate and report those experiments so that more data can be examined to provide improved guidance to users.
The objective of this study was to investigate the relative daytime and nighttime visibility of three crosswalk marking patterns: transverse lines, continental markings, and bar pair markings. This study collected information on the distance from the crosswalk at which the participant verbally indicated its presence. In total, 78 participants were used and were nearly evenly divided between groups by gender and by age (younger than 55 years old and 55 years old or older). The study was conducted in November 2009 using instrumented vehicles on an open road route on the Texas A&M University campus. Data were collected during two periods: daytime (sunny and clear or partly cloudy) and nighttime (street lighting on). Existing markings (six intersection and two midblock locations) and new markings installed for this study (nine midblock locations) were tested.
For the sites where markings were newly installed for this study, the detection distances for bar pairs and continental markings were similar, and they were statistically different from and longer than the detection distance for the transverse markings both during the day and at night. For the existing midblock locations, the continental markings were detected at about twice the distance upstream as the transverse markings during daytime conditions. This increase in distance reflects 8 s of increased awareness of the presence of the crossing for 30-mi/h operating speeds. Drivers also rated the appearance of markings on a scale of A to F. These results mirrored the findings from the detection distance evaluation. Overall, participants preferred the continental and bar pair markings over the transverse markings.
An evaluation methods report was developed as part of this FHWA project. The report provides traffic engineering practitioners with information on how to conduct an evaluation of traffic control devices for roadways associated with pedestrians and bicyclists. The evaluation methods report is designed for practitioners (State transportation departments and county/city engineers and planners). Personnel without high-level statistical analysis skills should be able to easily use and understand the report. The first step of any evaluation is to clearly formulate the research question by identifying the motorist, pedestrian, or bicyclist behavior that poses a safety or operations problem. Candidate traffic control devices and other countermeasures can then be identified as potential solutions to that problem. Evaluation methods described in this report include user surveys or interviews, visibility studies, driving performance studies, observational traffic studies, and crash analyses. The selection of the appropriate evaluation methods will weigh monetary cost, time, research aims, and available research equipment and staff.