policy brief

Electric Bike-share in the Sacramento Region is Replacing Car Trips and Supporting More Favorable Attitudes Towards Bicycling

Abstract

Bike-share services have rapidly expanded in cities worldwide and attracted substantial ridership, especially as electric and dockless bike- and scooter-share services have entered the market. These services have the potential to offer a healthier and more environmentally sustainable mobility option if used as an alternative to car travel and a connection to transit. However, little is known about the influence of bike-share systems on individual travel behavior; particularly if bike-share trips are replacing vehicle trips and increasing transit use. To address this knowledge gap, researchers at the University of California, Davis surveyed Sacramento-area residents before and after the 2018 implementation of a JUMP/Uberoperated dockless electric bike-share program to examine how the micromobility service influenced general travel behavior and attitudes. Surveys were sent to residents in downtown Sacramento, West Sacramento, and Davis within the bike-share service area and to a control group in Sacramento outside the service area. Key findings from the research are summarized in this brief.

policy brief

Clean Air in Cities: Impacts of the Layout of Buildings in Urban Areas on Pedestrian Exposure to Traffic-Related Pollutants

policy brief

Upzoning Under SB 50: The Influence of Local Conditions on the Potential for New Supply

Abstract

In this brief, the researchers explore what might happen were SB 50 to pass by taking a detailed look at local market conditions in four case study neighborhoods. Local context shapes financial and physical feasibility. When SB 827, the predecessor to SB 50, was under consideration, estimates of its impact on new housing supply were optimistic. Yet, most of these estimates focused on aggregate development potential and did not consider the on-the-ground reality of other zoning provisions that may influence development, what types of projects might pencil out, or what the existing stock looks like.

policy brief

Drivers of Partially Automated Vehicles are Making More Trips and Traveling Longer Distances

Abstract

Consumers are purchasing and using partially automated vehicles, yet little research has been conducted to understand how and if these vehicles are changing travel behavior. Fully automated, or driverless, vehicles are receiving much more research and policy attention but are still many years from market introduction. Research on fully automated vehicles has shown that, without proper policies in place, these vehicles could increase vehicle miles travelled (VMT). Tesla vehicle models with the ‘Autopilot’ feature are some of the most common partially automated vehicles on the road today. A partially automated vehicle provides advanced driver assistance by controlling steering, acceleration/ deceleration, and braking; however, the human driver is still considered to be in control of the vehicle and is expected to be attentive. A previous UC Davis study found that Tesla vehicle owners with the Autopilot feature drove more than those without Autopilot, but the study did not determine whether higher VMT was caused by Autopilot. To better understand whether Autopilot influences how much individuals drive, the UC Davis research team interviewed 36 Tesla Autopilot users to evaluate whether they experienced changes to their travel, and the reasons for any reported changes. Key findings from the interviews are presented in this brief.

research report

Travel Behavior Changes Among Users of Partially Automated Vehicles

Abstract

Partially automated battery electric vehicles (BEVs) are being sold to and used by consumers. Estimates indicate that as of the end of 2019, there were over 700,000 Partially Automated Tesla Vehicles—the subject of this study—on the roads globally. Despite this, little research has been done to understand how they may be changing travel behavior. In this study, qualitative interviews with 36 users of Tesla battery electric vehicles with Autopilot were conducted. The goal of this was to understand how Autopilot is used, user experiences of the system, and whether the system has any impact on drivers’ travel behavior. The focus of the last of these aims was to determine whether Autopilot could cause or was causing an increase in vehicle miles traveled (VMT) among the study participants. Results from the interviews showed that partial automation leads to consumers traveling by car more and being more willing to drive in congested traffic. These changes are due to increased comfort, reduced stress, and increased relaxation due to the partial automation system, and because of the lower running costs of a BEV. The results also point to a need for further research of partially automated vehicles that are already on the market, as 11 of 17 reasons for increased vehicle miles traveled that have been identified in modeling studies of fully automated vehicles (not yet commercially available) applied to users of Autopilot.

research report

Transportation, Quality of Life, and Older Adults

Abstract

Driving rates decline with age as vision, health, and cognitive ability cause some older adults to give up driving. Many older adults first gradually limit their driving as they age and later cease driving. Using data from the Health and Retirement Study (HRS), which surveys 22,000 older Americans every two years, the research team modeled the extent to which older drivers limit and stop driving. The data are longitudinal, allowing analysis of changes in driving and residential location as well as cohort effects that could not be studied using standard, cross-sectional survey data that only allow comparisons of different people at one point in time. The analysis shows that decisions to limit and eventually stop driving vary in statistically significant ways with sex, age, and health conditions. These relationships also differ by birth cohort. More recent cohorts are less likely to stop and limit driving than older ones. To analyze the relationship between residential location and driving behavior, the team linked the HRS data to census-tract-level data from the US Census and a categorization of community types. The research team found that residential density and other features of urban built environments are associated with changes in driving and vehicle ownership. HRS survey participants showed a greater propensity to reduce or give up driving if they resided in denser, more diverse, transit-oriented neighborhoods. People who prefer non-automotive modes of transportation may have been more likely than others to self-select into walkable and transit-rich areas. The findings should inform California’s strategic planning for aging and its community development policies. In addition to informing planning for the next generation of older Californians, this study demonstrated the utility of longitudinal information and models for the understanding of older populations and their travel.

research report

Investigating the Influence of Dockless Electric Bike-share on Travel Behavior, Attitudes, Health, and Equity

Abstract

Cities throughout the world have implemented bike-share systems as a strategy for expanding mobility options. While these have attracted substantial ridership, little is known about their influence on travel behavior more broadly. The aim of this study was to examine how shared electric bikes (e-bikes) and e-scooters influence individual travel attitudes and behavior, and related outcomes of physical activity and transportation equity. The study involved a survey in the greater Sacramento area of 1959 households before (Spring 2016) and 988 after (Spring 2019) the Summer 2018 implementation of the e-bike and e-scooter service operated by Jump, Inc., as well as a direct survey of 703 e-bike users (in Fall 2018 & Spring 2019). Among household respondents, 3–13% reported having used the service. Of e-bike share trips, 35% substituted for car travel, 30% substituted for walking, and 5% were used to connect to transit. Before- and after-household surveys indicated a slight decrease in self-reported (not objectively measured) median vehicle miles traveled and slight positive shifts in attitudes towards bicycling. Service implementation was associated with minimal changes in health in terms of physical activity and number of collisions. The percentages of users by self-reported student status, race, and income suggest a fairly equitable service distribution by these parameters, but each survey under-represents racial minorities and people with low incomes. Therefore, the study is inconclusive about how this service impacts those most in need. Furthermore, aggregated socio-demographics of areas where trips started or ended did not correlate with and therefore are not reliable indicators of, the socio-demographics of e-bike-share users. Thus, targeted surveying of racial minorities and people with low incomes is needed to understand bike-share equity.

research report

The Opportunity Cost of Parking Requirements: Would Silicon Valley be Richer if its Parking Requirements were Lower?

Abstract

We estimated the off-street parking supply of the seven most economically productive cities in Santa Clara County, California, better known as Silicon Valley. Using assessor data, municipal zoning data, and visual inspection with aerial imagery, we estimated that about 14 percent of the land area in these cities is devoted to parking and that over half the average commercial parcel is parking spaces. This latter fact suggested that minimum parking requirements, if binding, could depress Silicon Valley’s commercial and industrial densities, and; thus, its productivity. In an exploratory empirical exercise, we simulated a reduction in parking requirements from the year 2000 forward and showed that under conservative assumptions, the region could have added space for an additional 12,886 jobs, which is 43 percent of the actual job growth that occurred during that time. These additional jobs would be disproportionately located in the region’s highest-wage zip codes, further implying a large productivity gain.

presentation

3 Revolutions Policy Webinar Series

presentation

Caltrans Planning Horizons Webinar