This dissertation investigates the connection between perceived and actual bicycling risk, andhow they both affect and are affected by one’s attitudes, knowledge, behavior, and experiences. Understanding bicycling risk has gained importance as efforts by the U.S. Department of Transportation, the Environmental Protection Agency, the Centers for Disease Control & Prevention, and others have urged communities to increase cycling for its health, environmental, and social equity benefits. Research has identified numerous barriers to increased bicycling in the U.S., including topography, weather, and trip distance, but the barrier that appears most consistently between studies is the perceived hazard associated with cycling near motorists. Yet, little research has fully explored the concept of risk to understand its component parts, including how 1) various driver actions affect perceived and actual cycling risk, 2) reported crash statistics reflect perceived and actual risk, 3) roadway design preferences are affected by perceived risk, and 4) attitudes toward cycling and cycling risk—especially among drivers—influence support for bicycling in one’s community. A deeper understanding of perceived and actual risk is critical for knowing how to address it, and, ultimately, to encourage more people to bicycle. To begin to answer these questions and demystify bicycling risk, this dissertation employs three main methods: focus groups, an online survey (n=463), and an analysis of reported crash data from the San Francisco Bay Area, one of the regions at the forefront of cycling efforts in the U.S. 

My findings confirm that perceived and actual cycling risk influence the decision to bicycle, but indicate that the causal pathways are more nuanced than previously understood. First, my data suggest that cyclists experience two types of roadway risk: pervasive risk in the form of near misses that occur frequently, and acute risk that occurs when a cyclist is struck—a less frequent, but more injurious incident. Both types—but particularly near misses— significantly affect perceived risk for cyclists and their family and friends, yet we lack systematic data on near misses and are therefore almost completely ignorant about the extent and effect of their occurrence. Routinely-collected reported crash data provide only limited insight into the type and extent of risk cyclists experience. 

Second, roadway design preferences are significantly related to perceived risk, and particularly important for attracting new cyclists. Surprisingly, drivers and cyclists both prefer roadway designs with separated space for bicyclists, particularly if barrier-separated, regardless of cycling frequency. Shared space designs are less popular among drivers and much less popular among cyclists, particularly for people who might consider cycling but do not currently do so: only a tiny fraction of potential cyclists feel comfortable sharing space with drivers on commercial streets. 

Third, perceived cycling risk extends beyond fear of danger for oneself, and is significantly related to support for cycling in one’s community. Structural equation models of perceived cycling risk, attitudes, and behavior revealed that respondents are affected by their perceived risk as cyclists, but also as drivers sharing the roadway with cyclists they view as “scofflaws”, and the risks they project onto other cyclists—particularly those cycling with children. This multi-pronged belief in cycling risk significantly negatively affects bicycling support, including support for new bicycle facilities and public funding to encourage cycling. 

Based on these findings, I propose a revised theoretical framework for conceptualizing cycling risk and its influences. I conclude the dissertation with policy recommendations for addressing perceived risk.

This dissertation investigates the connection between perceived and actual bicycling risk, and how they both affect and are affected by one's attitudes, knowledge, behavior, and experiences. Understanding bicycling risk has gained importance as efforts by the U.S. Department of Transportation, the Environmental Protection Agency, the Centers for Disease Control & Prevention, and others have urged communities to increase cycling for its health, environmental, and social equity benefits. Research has identified numerous barriers to increased bicycling in the U.S., including topography, weather, and trip distance, but the barrier that appears most consistently between studies is the perceived hazard associated with cycling near motorists. Yet, little research has fully explored the concept of risk to understand its component parts, including how 1) various driver actions affect perceived and actual cycling risk, 2) reported crash statistics reflect perceived and actual risk, 3) roadway design preferences are affected by perceived risk, and 4) attitudes toward cycling and cycling risk--especially among drivers--influence support for bicycling in one's community. A deeper understanding of perceived and actual risk is critical for knowing how to address it, and, ultimately, to encourage more people to bicycle. To begin to answer these questions and demystify bicycling risk, this dissertation employs three main methods: focus groups, an online survey (n=463), and an analysis of reported crash data from the San Francisco Bay Area, one of the regions at the forefront of cycling efforts in the U.S.

My findings confirm that perceived and actual cycling risk influence the decision to bicycle, but indicate that the causal pathways are more nuanced than previously understood. First, my data suggest that cyclists experience two types of roadway risk: pervasive risk in the form of near misses that occur frequently, and acute risk that occurs when a cyclist is struck--a less frequent, but more injurious incident. Both types--but particularly near misses--significantly affect perceived risk for cyclists and their family and friends, yet we lack systematic data on near misses and are therefore almost completely ignorant about the extent and effect of their occurrence. Routinely-collected reported crash data provide only limited insight into the type and extent of risk cyclists experience.

Second, roadway design preferences are significantly related to perceived risk, and particularly important for attracting new cyclists. Surprisingly, drivers and cyclists both prefer roadway designs with separated space for bicyclists, particularly if barrier-separated, regardless of cycling frequency. Shared space designs are less popular among drivers and much less popular among cyclists, particularly for people who might consider cycling but do not currently do so: only a tiny fraction of potential cyclists feel comfortable sharing space with drivers on commercial streets.

Third, perceived cycling risk extends beyond fear of danger for oneself, and is significantly related to support for cycling in one's community. Structural equation models of perceived cycling risk, attitudes, and behavior revealed that respondents are affected by their perceived risk as cyclists, but also as drivers sharing the roadway with cyclists they view as "scofflaws", and the risks they project onto other cyclists--particularly those cycling with children. This multi-pronged belief in cycling risk significantly negatively affects bicycling support, including support for new bicycle facilities and public funding to encourage cycling.

Based on these findings, I propose a revised theoretical framework for conceptualizing cycling risk and its influences. I conclude the dissertation with policy recommendations for addressing perceived risk.

This paper presents findings from a recent study on roadway design preferences among pedestrians, drivers, bicyclists, and public transit users along a major urban corridor in the East San Francisco Bay Area.  Sponsored by the California DOT, the research focused on exploring design preferences that could increase perceived traffic safety, walkability, bikability, and economic vitality along urban arterials.  

Results from an intercept survey showed that all user groups desire similar roadway design features along the test corridor, which carries 25,000-30,000 motorists bi-directionally and has 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/improving driver behavior, increasing street lighting, and increasing traffic signals/stop signs. Similar preference alignment was found regarding 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.

This report contains five chapters, each with a number of sub-sections. Chapter I presents a summary of the research findings from the Literature Review and discusses their relevance and implications for urban arterials. Chapter II discusses the theoretical underpinnings of performance measurement and various approaches in the literature. It also profiles examples of “best practice” performance measures used by forward-thinking state transportation authorities to measure multimodal and “green” aspects of transportation system performance. Chapter III describes the federal, state, and agency policies and mandates that Caltrans is subject to relative to Complete Streets and environmental quality. Chapter IV presents the proposed Complete, Green Streets Performance Measure Framework, and includes discussion and recommendations related to setting targets and data collection. Finally, Chapter V provides conclusions and proposed next steps.

Pedestrians, bicyclists, drivers, and public transit users all desire similar roadway design features, at least according to findings from a recent intercept survey of 537 people along a major urban corridor in the San Francisco Bay Area. This research was sponsored by the California Department of Transportation to understand traveler preferences for street design that could increase perceived traffic safety, walkability, and bikability along urban arterials, as well as encourage economic vitality through increased patronage of local businesses.

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 remaining top five elements, while the same for all groups, were ordered slightly differently among them: slowing traffic/improving driver behavior, installing more traffic lights, and increasing the amount of street lighting. Similar preference alignment was found in response to a question about street improvements to encourage more visits to the corridor.

These findings suggest that design features generally thought to benefit one user group, such as bicycle lanes, may have unmeasured benefits for other user groups. Moreover, they offer evidence that focusing solely on specific user groups in the design process may miss opportunities to benefit multiple user groups through prioritizing a few design ideas. Overall, the

findings support the continued implementation of Caltrans’ Complete Streets policy.

The California Department of Transportation (Caltrans or “Department”) manages more than 15,000 miles of state highways, ranging in scale and function from local streets to interstate highways. Historically, Caltrans has been governed by the principles of highway engineering, which focus on providing mobility to motorized vehicles. Over the past decade, however, the Department has joined in a national movement to better incorporate non-motorized transportation and community-level outcomes into its transportation decision-making framework, embodied by the approach known as "Complete Streets." Recognizing that Caltrans’ current performance measurement system does not reflect this shift toward Complete Streets principles, researchers at the University of California, Berkeley created new measures to more accurately gauge Departmental progress toward these objectives. This paper elaborates on a proposed framework of performance measures for encouraging non-motorized transportation and increasing the environmental sustainability of the transportation system. The framework focuses on urban arterials, which carry high amounts of multimodal traffic and constitute 26% of California’s urban roadway network. Based on Complete Streets principles and the findings from an extensive literature review, the proposed framework compliments Caltrans’ current performance measurement system and presents an opportunity for the Department to become a national leader in encouraging non-motorized transportation and preserving the environment.

This literature review is the culmination of the first phase of a research study directed at reviewing, analyzing, and quantifying the impacts of transportation corridors’ design features on user behavior, safety, community and economic vitality, environmental quality, and public health. The research project aims to provide transportation agencies with information to facilitate more defensible measurement of the effects of corridor design features on the quality of life of the communities and rural environments through which they run. The research is directed at transportation corridors under the jurisdiction of state highway departments, and is concerned with controlled-access freeways, expressways, arterials, and “main street” highways. The focus is primarily on corridor roadsides, rather than vehicle roadbeds, because these are the interface zones between roadways and communities or the rural landscape. (See Table 4: Caltrans Terminology for definitions of “roadside” and “roadbed.”) Because of their potential contributions to quality of life issues, attention has also been paid to non-roadside design elements that contribute to traffic calming, walkability, and bikability, such as travel lane widths, crosswalks, and bicycle lanes. Funding and time constraints necessarily limit the scope of the research project such that transit-related roadside design elements, such as bus shelters, are not considered.

This literature review assesses the recent published research that has been identified as most relevant for this research project. The ultimate goal of the research project is to develop quantifiable performance measures derived from this review of the research, and then to test the performance measures via case study analysis of selected transportation corridors.