Data collection

A Comparative Safety Study of Limited versus Continuous Access High Occupancy Vehicle (HOV) Facilities

Jang, Kitae
Ragland, David R.
Chan, Ching-Yao
2009
The report summarizes the findings from comparative studies of safety performance between two different types of High Occupancy Vehicle (HOV) facilities in California - continuous access versus limited access. The findings show that HOV facilities with limited access offer no safety advantages over those with continuous access, whether measured by percentage of collisions, collisions per mile, collisions per VMT, or collision severity. As part of the present research, the authors investigated the relationship...

Seamless Travel: Measuring Bicycle and Pedestrian Activity in San Diego County and its Relationship to Land Use, Transportation, Safety, and Facility Type

Jones, Michael G.
Ryan, Sherry
Donlon, Jennifer
Ledbetter, Lauren
Ragland, David R.
Arnold, Lindsay S.
2010

This paper provides the data collection and research results for the Seamless Travel project. The Seamless Travel Project is a research project funded by Caltrans and managed by the University of California Traffic Safety Center, with David Ragland, PhD., as the Principal Investigator and Michael Jones as the Project Manager. The project is funded by Caltrans Division of Innovation and Research and is being conducted by the Traffic Safety Center of University of California Berkeley and Alta Planning + Design. Measuring bicycle and pedestrian activity is a key element to achieving the goals...

Safe Routes to School Local School Project: A health evaluation at 10 low-income schools

Cooper, Jill F.
McMillan, Tracy
2010

The Safe Routes to School National Partnership (Partnership) founded the Local School Project (Project) in 2008 to assist ten schools in lowincome communities to: 1) develop and evaluate a school-based SRTS program, 2) build local capacity to apply for state or federal SRTS funding, and 3) increase safe walking and bicycling to and from the school and in the community. The Centers for Disease Control and Prevention, Kaiser Permanente, and the Robert Wood Johnson Foundation provided funding for the Project. This report presents the results, lessons learned and recommendations...

Evaluation of Traffic and Environment Effects on Skid Resistance and Safety Performance of Rubberized Open-grade Asphalt Concrete

Oh, Soon Mi
Ragland, David R.
Chan, Ching-Yao
2010

Wet pavement-related collisions represent a significant traffic safety concern, due in part to the lack of adequate friction between tire and pavement, known as skid resistance. State agencies employ a skid number (SN) system, based on a standard test procedure in which a locked wheel is towed at 40 mph and the skid number (SN40) is calculated from the measured resistance. SN40 is used as a reference value for speeds both greater than and less than 40 mph. For most Departments of Transportation (DOTs) in the nation, excluding California, pavements for which the SN40 is below 30 are deemed...

Cross-Section Designs for the Safety Performance of Buffer-Separated High-Occupancy Vehicle (HOV) lanes

Jang, Kitae
Kang, Sanghyeok
Seo, Jongwon
Chan, Ching-Yao
2011

High-occupancy vehicle (HOV) lanes have been deployed as a tool for traffic management in urban freeway systems to improve reliability and mobility of trips. As they are planned to traverse crowded urban areas, it is often difficult to acquire sufficient right-of-way for retrofitting HOV lanes to existing freeway systems with recommended cross-sectional design. The present study proposes a methodology to determine the optimal set of cross-sectional design for safety performance by evaluating individual impact of each design element on safety as well as tradeoffs between them. Detailed...

Modeling Bicycle Passing Maneuvers on Multilane Separated Bicycle Paths

Li, Zhibin
Wang, Wei
Liu, Pan
Bigham, John M.
Ragland, David R.
2012

Bicycle passing maneuvers represent interferences between bicycle travelers and are important operational attributes of bicycle traffic. The number of bicycle passing maneuvers has been used to evaluate the level of service (LOS) of off-street bicycle facilities. The primary objectives of this paper are to propose a method to model bicycle passing maneuvers on multilane bicycle paths with heavy bicycle traffic and explore the characteristics of those passes. The authors classified bicycle passing maneuvers into free, adjacent, and delayed passes according to the lateral distance...

Building a Highway Linear Referencing System from Preexisting Reference Marker Measurements for Transportation Data Management

Bigham, John M.
Kang, Sanghyeok
2013

To manage events associated with highways, data systems have been developed to store relevant event information. To reap the full benefits of geographic information system technologies, the relative locations can be integrated into a linear referencing system. The objective of this paper is to present a methodology for building a highway linear referencing system by applying preexisting marker measurements to a digital street network. The system was developed for locating motor vehicle collisions in California and resulted in improved accuracy compared to a previously developed...

Airports and Bicycles: what are the obstacles and incentives for operators to improve bicycle access?

Orrick, Phyllis
Frick, Karen Trapenberg
2013

In this paper we use a case study approach to examine how airport operators are addressing bicycle access to their properties and the motivations and obstacles they face, in light of new policies to integrate bicycles, along with transit and walking, into transportation planning, design and construction, and to increase bicycles’ role in the transportation system. Eight influential elements emerged from our review of policy documents and research literature. We used them to guide interviews with key informants. The eight elements are: governance structure, location, access roads,...

Safe Routes to Transit Program Evaluation Final Report

Sanders, Rebecca L.
Weinzimmer, David
Dittrich, Heidi
Cooper, Jill F.
2014

Safe Routes to Transit (SR2T) was initiated in 2004 with the adoption of the San Francisco Bay Area’s Regional Measure 2 which established a $1 increase in Bay Area bridge tolls. The intended purpose of this funding was to support various transportation projects within the region in order to reduce congestion along the seven state-owned toll bridge corridors. Consistent with this purpose, the SR2T Program was awarded $20 million to fund enhancements to increase walking and cycling to regional transit stations. SR2T funds were used for the following improvements, among others: ssecure...

Variations in Teens' Perception of Risk Factors for Teen Motor Vehicle Collision Injuries

Chen, Katherine L.
Cooper, Jill F.
Grembek, Offer
Henk, Russell
Tisdale, Stacey M.
2014

Teen drivers, especially males, are known to be at greater risk of being involved in a motor vehicle collision than any other age group. While novice teen drivers’ primary risk factors are commonly known, less is known about what teens perceive as risk factors for peers getting hurt or killed in motor vehicle collisions. This mixed methods study uses survey data from the Teens in the Drivers Seat (TDS) program in California to explore (1) teens' perceived risk factors for motor vehicle collision injury; and (2) the relationship between perceived risks and age, gender, and driving...