Road User Behavior

Safety and Other Impacts of Vehicle Impound Enforcement

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

This study was conducted by a team of researchers at the Institute of Transportation Studies, University of California at Berkeley, with funding from the California Office of Traffic Safety. Ted Chira-Chavala directed the study, coordinated the write-up of the final report, and wrote many chapters. Douglas Cooper was the key researcher, who performed the literature review, worked with key personnel of Upland Police Department to acquire essential data for the evaluation, analyzed the data, and contributed significantly to all chapters. David Gillen performed all time-series analyses and...

The Effects of Transportation Corridors' Roadside Design Features on User Behavior and Safety, and Their Contributions to Health, Enviornmental Quality, and Community Economic Vitality: a Literature Review

Macdonald, Elizabeth
Sanders, Rebecca
Supawanich, Paul
2008

A transportation corridor communicates many things to its users through its design elements. What it communicates can affect the travel mode a user decides to take, the speed at which a motorist decides to drive, whether a pedestrian will walk along or across a street, and whether a resident will bicycle to local shops. Design elements give visual cues to the users of transportation corridors that let them know where they are and how to behave. The vehicle lane widths, presence or absence of sidewalks, and presence or absence of buffering elements such as street trees and parked cars all...

The Continuous Risk Profile Approach for the Identification of High Collision Concentration Locations on Congested Highways

Chung, Koohong
Ragland, David R.
Madanat, Samer
Oh, Soon Mi
2009

This paper documents a new method for monitoring traffic collision data from continuous roadway facilities to detect high collision concentration locations. Many existing methods for detecting collision concentration locations require segmentation of roadways and assume traffic collision data are spatially uncorrelated, resulting in both false positives (i.e., identifying sites for safety improvements that should not have been selected) and false negatives (i.e., not identifying sites that should have been selected). The proposed method does not require segmentation of roadways;...

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...

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...

Applying Safety Treatments To Rail-Highway At-Grade Crossings

Cooper, Douglas L.
Ragland, David R.
2012

At-grade rail crossings provide different levels of warnings and/or barriers to alert drivers to the potential dangers presented by approaching trains. For some drivers, an activated warning system, rather than being a signal to stop, merely serves as a cue for the need to make a decision whether or not to cross. In California, for the ten-year period from 2001 to 2010, the result was 1,033 trainvehicle crashes resulting in 157 deaths and 458 injuries. The best solution to rail crossing crashes is to remove the need for the driver to engage in a potentially faulty decision-making process...

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...

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...

Predictors of Nonstandard Helmet Use Among San Francisco Bay–Area Motorcyclists

Tsui, Casey K.
Rice, Thomas M.
Pande, Swati
2013
Objective: The use of helmets that do not comply with safety standards is common in California. The objective of this study was to describe the use of these nonstandard helmets among San Francisco Bay–area (SFBA) motorcyclists and to identify personal and motorcycle characteristics that are associated with the use of nonstandard helmets. Methods: A survey of 860 SFBA motorcyclists was conducted. Log-binomial regression was used to estimate risk ratios to compare probabilities of nonstandard helmet use. Results: Fifteen percent of motorcyclists reported wearing a nonstandard helmet sometimes...