Rebecca L. Sanders

Do All Roadway Users Want the Same Things

Presented here are findings from a recent study on roadway design preferences of pedestrians, drivers, bicyclists, and public transit users along a major urban corridor in the east San Francisco Bay Area in California. Sponsored by the California Department of Transportation, the research focused on exploring design preferences that could increase perceived traffic safety, walkability, bikeability, and economic vitality along urban arterials. Results from an intercept survey showed that all user groups desired similar roadway design features along the test corridor, which carried 25,000 to 30,000 motorists bidirectionally and had comprehensive sidewalk coverage but no bicycle facilities. In an open-ended question about street improvements to enhance perceived traffic safety, all respondent groups requested the same top five improvements. Bicycle lanes were ranked first by pedestrians, drivers, and bicyclists (fifth by public transit respondents) and improved pedestrian crossings were ranked second by pedestrians, drivers, and public transit users (third by bicyclists). The other top five suggestions were the same for all groups though ordered slightly differently: slowing traffic and improving driver behavior, increasing street lighting, and increasing traffic signals and stop signs. Similar preference alignment was found for street improvements to encourage more visits to the corridor. These findings suggest that design features generally thought to benefit one road user group, such as bicycle lanes for bicyclists, may also benefit other users. Moreover, these results provide evidence that roadway planning can take advantage of synergistic opportunities to benefit multiple user groups by implementing a few key design interventions. Overall, the findings support the continued implementation of complete streets principles and policies.

Pedestrian Safety Practitioners’ Perspectives of Driver Yielding Behavior Across North America

This paper presents results from a recent Internet survey of practitioners in the pedestrian safety field about their perceptions of driver yielding behavior in cities throughout North America. As one of the first studies to attempt to understand driver and pedestrian interactions from a macro perspective, this research combined perceptions of local driver yielding rates in three crosswalk scenarios with open-ended comments to understand factors that may influence driver yielding behavior. Responses from 387 practitioners in 171 cities suggested that rates of driver yielding to pedestrians in marked crosswalks were related to characteristics such as social norms, roadway design, law enforcement, and pedestrian volumes. Respondents generally indicated that drivers were more likely to yield to pedestrians on roadways with fewer lanes and slower travel speeds. However, the results also suggested notable geographic differences in yielding culture. Practitioners indicated that crosswalk laws were rarely enforced in most communities. A theoretical framework for future empirical research on driver yielding as it relates to driving and walking culture, roadway design, crosswalk laws, and enforcement is provided.

Changing the Future? Development and Application of Pedestrian Safety Performance Functions to Prioritize Locations in Seattle, Washington

This study aimed to use robust analysis methods to identify and screen locations at risk for pedestrian crashes and injuries to help Seattle, Washington, a Vision Zero city, broaden treatment priorities beyond only high-crash locations. For this objective, data from the entire network were used to develop safety performance functions (SPFs) for two pedestrian crash types: total pedestrian crashes at intersections (a high frequency type) and a subset of intersection crashes involving through motorists striking crossing pedestrians (a high severity type). Many variables from roadway, built environment, census, and activity measures were tested. A similar but not identical set of variables, including measures of activity and intersection size and complexity, significantly contributed to crash prediction in both models. Pedestrian volume exhibited a curved relationship to crashes and demonstrated a tendency for expected crashes to begin to decline above a threshold value; however, the causes of this relationship were unknown. The SPFs were used in several ranking methods, including SPF-predicted crashes, empirical Bayes estimated crashes, and potential for safety improvement, to aid in prioritization of locations that might have been candidates for safety improvement but that had not necessarily experienced a high frequency of crashes. On the basis of this example, this approach is feasible for jurisdictions that wish to be more proactive in addressing potential crashes and injuries. Jurisdictions must, however, begin routinely collecting the data needed to implement the method efficiently.

Perceived Safety and Separated Bike Lanes in the Midwest: Results from a Roadway Design Survey in Michigan

This article presents the results of an address-based sample survey (n = 351) conducted in the fall of 2016 for the Michigan Department of Transportation (MDOT) as part of an effort to provide guidance for building sidepaths. The survey investigated attitudes toward bicycling among drivers and bicyclists, bicycling habits, barriers to bicycling, and roadway design preferences regarding bicycle infrastructure in Michigan. In particular, this survey explored design preferences while bicycling with children, bicycling by oneself, and driving. Safety emerged as a key barrier to bicycling, as did distance, weather, and the difficulty of carrying things or traveling with others. Roadway design preferences were clearly weighted toward greater separation when sharing the roadway whether as a bicyclist or a driver, and this trend was most pronounced (p < 0.001) when considering bicycling with children. In all cases, ratings for one-way separated bike lanes were similar to those for sidepaths, suggesting that separated bike lanes could be a key part of addressing the safety and comfort concerns of more cautious riders. Preferences for separation were strongly associated with perceived safety as a barrier. These results were even stronger for non-transport-cyclists, although all groups, regardless of frequency or type of bicycling, preferred more separation. These results corroborate past research and add compelling evidence for separated facilities as a key part of expanding the potential for bicycling trips in general, and particularly with children. The survey findings will inform guidance about sidepath design for MDOT.

Ballpark Method for Estimating Pedestrian and Bicyclist Exposure in Seattle, Washington: Potential Option for Resource-Constrained Cities in an Age of Big Data

The Moving Ahead for Progress in the 21st Century Act emphasized the use of data and performance measurement to track progress toward its transportation policy and safety goals. As U.S. cities and states implement policies to eliminate traffic deaths and serious injuries, exposure data are needed to contextualize crash analyses and prioritize effective countermeasures to reduce future risk. However, comprehensive counting programs are resource intensive. Research suggests that so-called big data can supplement traditional counting programs, fill the data gap, and allow for more robust exposure modeling. This paper presents the results of an abbreviated exposure estimation process to develop ballpark pedestrian and bicycle estimates for the city of Seattle, Washington, conducted as part of a major bicycle and pedestrian safety analysis for Seattles Vision Zero effort. This paper contributes to existing research on exposure estimation and demonstrates a case study of practice-ready bicycle and pedestrian exposure models. Because of budget and time constraints, the exposure estimates used available data sources and were based on models from earlier bicycle and pedestrian volume estimation studies. The pedestrian model (pseudo-R2 = .76) fit with published models, and the bicycle model had decent explanatory power (pseudo-R2 = .57). After Strava data were added to the bicycle model, the explanatory power rose to 62% and the model was simplified. The estimates were tested in a multivariate crash analysis and used to support countermeasure identification and project prioritization. This type of abbreviated process may be appropriate for other cities seeking to estimate exposure but without the resources for a full-scale estimation effort.

Evaluation of the Safe Routes to Transit Program in California

This paper elaborates on findings from an evaluation of the San Francisco Bay Areas Safe Routes to Transit (SR2T) program in California. This program funded enhancements to increase walking and cycling to regional transit stations. To understand how the program influenced travel choices, behavior, and perceptions of safety and local air quality, the study surveyed transit users and observed driver, pedestrian, and bicyclist behavior in the periods before and after the enhancements were made at multiple transit stations. Data from the treatment and control stations suggested that the streetscape and roadway improvements made through the SR2T program positively influenced the propensity to walk, bicycle, and take the bus to transit stations, as reported through surveys. In particular, the results showed that walking and bicycling increased by 3% at treatment sites compared with control sites. Bicycling also increased at control sites; this factor indicated a general societal shift. Furthermore, driving decreased 2.5% at treatment sites. Perceived air quality, in general, improved in the posttime period. When asked about perceived traffic risk, bicyclists more than pedestrians reported feeling safer on the road, with 10% of the bicyclists, on average, feeling safer after the improvements. There were also economic benefits from this project—pedestrians and bicyclists were overrepresented in those who stopped en route to transit for food and drink. The evidence suggested that the SR2T program positively affected the decision to walk and bicycle to access transit. The program is recommended for expansion to additional sites.