Travel Behavior

Impacts of California's Graduated Licensing Law of 1998: An assessment by the Institute of Transportation Studies at UC Berkeley of the effects of the law on fatal and injury crashes of 16 year-old drivers

Cooper, Douglas
Gillen, David
Atkins, Frank
2004

In July 1998 California changed its graduated driver licensing laws (GDL) for new drivers under the age of 18 to include restrictions on hours of driving, carrying teen-age passengers, and requiring more adult supervised driving practice. With fatal and injury crash data from California's Statewide Integrated Traffic Records System, this study, sponsored by the California State Automobile Association, used standard regression analysis as well as the Bai-Perron stochastic multiple structural break model to determine the effect of the law on teen-age passengers and crash rates of 16 year-old...

To Pool or Not to Pool? Understanding the Time and Price Tradeoffs of OnDemand Ride Users – Opportunities, Challenges, and Social Equity Considerations for Policies to Promote Shared-Ride Services

Shaheen, Susan, PhD
Lazarus, Jessica
Caicedo, Juan
Bayen, Alexandre, PhD
2021

On-demand mobility services including transportation network companies (also known as ridesourcing and ridehailing) like Lyft and Uber are changing the way that people travel by providing dynamic mobility that can supplement public transit and personal-vehicle use. However, TNC services have been found to contribute to increasing vehicle mileage, traffic congestion, and greenhouse gas emissions. Pooling rides ⎯ sharing a vehicle by multiple passengers to complete journeys of similar origin and destination ⎯ can increase the average vehicle occupancy of TNC trips and thus mitigate some of...

The Impact of COVID-19 on the Mobility Needs of an Aging Population in Contra Costa County

Ragland, David R, PhD, MPH
Schor, Glenn, PhD, MPH
Felschundneff, Grace
2020

In 2018, SafeTREC conducted a survey on transportation mobility issues among older adults in California. A follow-up survey planned for 2020, just as the COVID-19 pandemic changed life for all residents, was redesigned to assess mobility needs and changes during the Shelter-in-Place order and focused on COVID-19 impacts. Results indicate that the COVID-19 pandemic and subsequent Shelter-in-Place order have had a major impact on senior mobility. Communications for many were restricted to phone, email, texts, social media and video chats. Among those with a medical problem, just over 60%...

Empirical Study of Ramp Metering and Capacity

Cassidy, Michael J.
Rudjanakanoknad, Jittichai
2002

Traffic data near the junction of a single-lane on-ramp (with a ramp meter) and a three-lane freeway were measured for six weekdays during the rush and studied. On each of these days, the merge became a bottleneck with queue discharge rates that were substantially lower than the flows that had passed the merge prior to the bottleneck's activation. On some days, these earlier high flows persisted for many minutes. The bottleneck always occurred when inflows from the on-ramp surged in the presence of high flows arriving from the freeway. Often, the on-ramp surges persisted for no longer than...

Measuring the influence of recurring sporting events on freeway characteristics

Seeherman, Joshua
Anderson, Paul
2017

Freeway traffic is subject to the effects of recurring and non-recurring events. Changes in the traffic stream as a result of recurring special events, specifically sports, is an area that is not well researched. This study examined freeway detectors adjacent to two baseball stadiums in California to analyze the contribution of a baseball game to freeway flow and occupancy for weekday evening games. In addition, hourly volumes on local rail transit were analyzed in the San Francisco case. Findings include a statistically significant effect of baseball increasing the flow by approximately 1...

A Behavioral Theory of Multi-Lane Traffic Flow Part II: Merges and the Onset of Congestion

Daganzo, Carlos F.
1999

This paper examines the behavior of multi-lane freeway traffic past on-ramps, building on the continuum model of part I and focusing on the onset of congestion. The main complication with merges is that rabbits (fast vehicles) entering from an on-ramp usually stay on the shoulder lane(s) of the freeway for some distance before merging into the fast lane(s). An idealization is proposed where this distance is taken to be the same for all vehicles. As a result, the system behaves as if there was a fixed buffer zone where entering rabbits cannot change lanes. The model of part I is extended to...

“Don’t Keep Us Out of the Revolution!”: Accessibility and Autonomous Rideshare in California

Heuser, Katie L.
2024

Robotaxi services, or rideshare operated by autonomous vehicles, present an opportunity for independent and convenient transportation for people with disabilities. The proliferation of robotaxis in California has been met with mixed reactions from the disability community. To better understand perceptions of and expectations for robotaxis, this report uses semi-structured interviews with representatives from disability advocacy organizations. For many people with disabilities, especially for people with intellectual, developmental, and/or physical disabilities, robotaxis are inaccessible....

Safety and Other Impacts of Vehicle Impound Enforcement

Cooper, Douglas
Chira-Chavala, T.
Gillen, David
2000

California vehicle impound law took affect on January 1, 1995. The law allows a police officer to seize a vehicle operated by a person whose license is suspended or revoked or who has never been issued a license. The seized vehicle shall then be impounded for 30 days. In California, a driver must be stopped for some other infraction before his/her license can be checked. The City of Upland, located in western San Bernardino County, has a population of 67,453 residing in a 15.2 square-mile area. The city’s 169 miles of roadways support about 600,000 vehicle-miles of travel daily. Upland...

Pattern Recognition for Curb Usage

Arcak, Murat PhD
Kurzhanskiy, Alex A., PhD
2024

The increasing use of transportation network companies and delivery services has transformed the utilization of curb space, resulting in a lack of parking and contributing to congestion. No systematic method exists for identifying curb usage patterns, but emerging machine learning technologies and low-tech data sources, such as dashboard cameras mounted on vehicles that routinely travel the area, have the potential of monitoring curb usage. To demonstrate how video data can be used to recognize usage patterns, we conducted a case study on Bancroft Way in Berkeley, CA. The project collected...

Struggling to Connect: Housing and Transportation Challenges of Low-Income Suburban Residents in the San Francisco Bay Area

Pan, Alexandra
Deakin, Elizabeth, PhD
Shaheen, Susan, PhD
2024

Suburban areas have lower density development than urban areas, which may make them less accessible for the growing population of low- and moderate-income suburban residents, particularly those without a personal vehicle. This research examines factors that lead these households to move to suburban areas and identifies accessibility barriers they face. We use a mixed-methods approach with Public Use Microdata Sample (PUMS) data from the U.S. Census, online/in-person surveys (n=208), and interviews conducted in English and Spanish (n=25) with households in Contra Costa County with an income...