State-of-the-art methods for the safe and efficient design of bicycle facilities are based on difficult to collect data and potentially dubious assumptions regarding cyclist behavior. Simulation models could offer a way forward, but existing bicycling models in the academic literature have not been validated using actual data. This paper attempts to address both of these shortcomings simultaneously by conducting a field study to obtain real-world bicycle data and implementing a simulation using a multilane and inhomogeneous cellular automata model to reproduce the observations. The resulting model is found to emulate field conditions while possibly under-predicting bike path capacity. The analysis indicates that the model's potential as for planning could be high given additional work on the underlying model specification and the collection of additional data.

Given current concerns surrounding regional air pollution, climate change and urban congestion, this research is timely. If we begin to see more substantial mode shifting to non-motorized modes, this and similar models could become standard tools in the city or regional planner's toolkit.

After a discussion of the context in which this research is being conducted, we review the relevant literature on bicycle facility design and bicycle traffic operation, before summarizing the real-world data collection methods and results. The simulation model is then presented along with results and discussion comparing the modeled to observed data. We conclude with suggestions for future work in data collection and model development.

Current concerns surrounding regional air pollution, climate change, rising gasoline prices and urban congestion could presage a substantial increase in bicycle mode share. However, state-of-the-art methods for the safe and efficient design of bicycle facilities are based on difficult to collect data and potentially dubious assumptions regarding cyclist behavior. Simulation models offer a way forward, but existing bicycling models in the academic literature have not been validated using actual data. This paper addresses these shortcomings by obtaining real-world bicycle data and implementing a multilane, inhomogeneous cellular automaton simulation model that can reproduce observations. The existing literature is reviewed to inform the data collection and model development. It is found that the model emulates field conditions while possibly under-predicting bike path capacity. Since the simulation model can “observe” individual cyclists, it is ideally suited to determine level of service based on difficult to observe cycling events such as passing. The conclusion suggests future work on data collection and model development.

In this paper we seek to document what, if any, divergences exist between how experts and ‘lay’ people conceptualize the energy used in automobiles, motivated by previously-documented divergences in the home energy sector. From a total of 15 interviews with 19 individuals, we identify several common ways ‘lay’ people think about automobile energy use, and draw a number of conclusions relevant to the development of transportation energy policy. In our informants’ minds, automobiles use gasoline, rather than a more generic form of energy, and they therefore have a difficult time comparing energy use across activities. When asked to compare their total energy use for both residential and transportation activities, informants used dollars to provide a common unit of measurement. Our informants thought of automobile efficiency almost exclusively as fuel economy and were aware of it, albeit based on inconsistent methods and varying degrees of rigor. They measure fuel economy almost exclusively in miles per gallon and demonstrated easy familiarity with this measure—they were very comfortable comparing their present cars with past cars, or with other cars in terms of fuel economy. However, the prevalence of this volumetric, more-is-better measure may present challenges for communication as alternative fuels (e.g. electricity) gain market share because such fuels may not comport with this measure in an intuitive way. In-dash fuel economy displays seem to have made some drivers more aware that driving behavior is a factor in realized fuel economy, although it appears that this link could be strengthened if displays were to provide more pertinent information. However, in contrast to home energy use where active management is a primary means of saving energy, automobile energy use is considered primarily at the point of purchase rather than in daily driving decisions. Finally, our informants tended to evaluate their fuel economy relative to a benchmark of some kind, whether CAFE standards or their perception of the fleet (or vehicle class) average.

Disparities in the distribution of transportation system benefits and burdens are significant and have persisted despite the efforts of many to reduce or eliminate them. Although transportation plans and projects must be assessed for their distributive effects in accordance with U.S. laws and regulatory guidance, these analyses rarely uncover findings that result in changes to decisions already made or the creation of entirely new projects or policies. This outcome is due in part to limitations associated with transportation governance institutions including metropolitan planning organizations (MPOs), specifically those related to inequitable access to political power and representation. It is also due to methodological choices and limitations in the quantitative analyses that are conducted to understand (and ideally avoid or mitigate) impacts.

This policy brief summarizes findings from the white paper that assesses academic research and transportation planning practice to provide a shared understanding of the definitions, challenges, and opportunities in this field, thereby enabling often-conflicting parties to collaborate in achieving a common goal: transportation equity.

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In this paper we seek to document what, if any, divergences exist between how experts and ‘lay’ people conceptualize the energy used in automobiles, motivated by previously-documented divergences in the home energy sector. From a total of 15 interviews with 19 individuals, we identify several common ways ‘lay’ people think about automobile energy use, and draw a number of conclusions relevant to the development of transportation energy policy.

In our informants’ minds, automobiles use gasoline, rather than a more generic form of energy, and they therefore have a difficult time comparing energy use across activities. When asked to compare their total energy use for both residential and transportation activities, informants used dollars to provide a common unit of measurement.

Our informants thought of automobile efficiency almost exclusively as fuel economy and were aware of it, albeit based on inconsistent methods and varying degrees of rigor. They measure fuel economy almost exclusively in miles per gallon and demonstrated easy familiarity with this measure—they were very comfortable comparing their present cars with past cars, or with other cars in terms of fuel economy. However, the prevalence of this volumetric, more-is-better measure may present challenges for communication as alternative fuels (e.g. electricity) gain market share because such fuels may not comport with this measure in an intuitive way.

In-dash fuel economy displays seem to have made some drivers more aware that driving behavior is a factor in realized fuel economy, although it appears that this link could be strengthened if displays were to provide more pertinent information. However, in contrast to home energy use where active management is a primary means of saving energy, automobile energy use is considered primarily at the point of purchase rather than in daily driving decisions. Finally, our informants tended to evaluate their fuel economy relative to a benchmark of some kind, whether CAFE standards or their perception of the fleet (or vehicle class) average.

Achieving transportation equity is a transportation system goal that is becoming increasingly important in both the public sector and academia. An equitable transportation system would ensure that the benefits and burdens created by transportation projects, policies, and plans are shared fairly such that no groups would be unduly burdened by a lack of access to adequate transportation nor by the negative effects of proximity to transportation infrastructure. Such a system would also ensure that public participation in the transportation decision making process is meaningful and effective and that participants would have a reasonable expectation that their voices would be heard and decisions changed in response. The purpose of this white paper is to provide an overview, synthesis, and critical assessment of academic research and transportation planning practice in order to provide a shared foundation for the many parties working toward equitable transportation systems. Throughout, the authors highlight key dimensions of transportation equity to provide a common language and to facilitate collaboration among transportation decision makers, planners, policymakers, advocates, and the general public. These groups will also be able to use the white paper to identify key research needs and promising strategies for advancing transportation equity goals. The authors hope that this shared understanding of the definitions, challenges, and opportunities in this field will enable often conflicting parties to collaborate in achieving the common goal of transportation equity: in other words, to “get there from here.”

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Plans crafted by metropolitan planning organizations (MPOs) lay out how billions of dollars in transportation investments will be made over a 20 to 30-year time horizon. Federal transportation authorizations require MPOs to identify and track key indicators of system performance (e.g. collision rates, emissions, congestion) to ensure that they are stewarding public funds wisely to meet specific goals related to safety, environmental performance, and congestion mitigation, among other areas. Concerns related to preventing discriminatory impacts of planning activities, motivated by Title VI of the 1964 Civil Rights Act, also compel agencies to assess the impacts of plans on different demographic groups. At the same time, there is a growing desire among transportation planning agencies to develop transportation and land use plans that shift travel behavior away from driving and towards more active travel modes. Research has shown that living in areas where walking and bicycling are convenient leads to greater use of those modes, which can lead to improved health outcomes due to increases in physical activity. But increasing non-motorized travel can also increase active travelers’ risk of traffic injury and exposure to air pollution. Analytical tools that assess the tradeoffs between transportation plan alternatives are needed to inform public debate and ensure that gains in some health outcomes are not being undermined by losses elsewhere. Additionally, questions remain about who will benefit from plans that promote increases in active travel. The aim of this project is to investigate the distribution of public health impacts resulting from a regional transportation plan in the six-county Sacramento Area Council of Governments (SACOG) region.

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