Motorized Vehicle Safety

Surrogate safety measure for evaluating rear-end collision risk related to kinematic waves near freeway recurrent bottlenecks

Li, Zhibin
Ahn, Seongchae
Chung, Koohong
Ragland, David R.
Wang, Wei
Yu, Jeong Whon
2013

This study presents a surrogate safety measure for evaluating the rear-end collision risk related to kinematic waves near freeway recurrent bottlenecks using aggregated traffic data from ordinary loop detectors. The attributes of kinematic waves that accompany rear-end collisions and the traffic conditions at detector stations spanning the collision locations were examined to develop the rear-end collision risk index (RCRI). Together with RCRI, standard deviations in occupancy were used to develop a logistic regression model for estimating rear-end collision likelihood near freeway...

Develop Methods to Reduce or Prevent Backing Crashes

Cooper, Douglas L.
Duffy, Sarah
Orrick, Phyllis
Ragland, David R.
2009

Workplace motor vehicle incidents at Caltrans are a significant cause of injuries, employee lost time, and property damage. Because backing crashes are major contributors to motor vehicle incidents, identifying and promoting methods of reducing backing accidents is a top priority. According to internal Caltrans’ data, 92.3% of workplace backing crashes were preventable by the driver. Backing crashes are the single largest category of preventable crashes, representing 30% of preventable crashes in the Caltrans fleet. From 1998 through 2007, preventable backing crashes cost Caltrans at least...

Methods for Identifying High Collision Concentration Locations for Potential Safety Improvements

Geyer, Judy
Lankina, Elena
Chan, Ching-Yao
Ragland, David R.
Pham, Trinh
Sharafsaleh, Mohammad A.
2008

The California Department of Transportation (Caltrans) uses Table C and related documents to identify and to investigate locations within the state highway system where a relatively large number of collisions occur. In earlier years, a task force evaluated the process of generating and using these reports and found that there was much room for improvements. A list of recommendations was made. The efforts undertaken within this project is part of the effort to make the process of safety investigations and improvements more efficient and productive. This report summarizes the work carried...

Applying Safety Improvements to Fleet Vehicles

Cooper, Douglas L.
Sharafsaleh, Mohammad A.
Ragland, David R.
Begley, Loida
Kim, Yong Hee
Jin, Eui Jae
2007

The safety of both employees and the motoring public is of paramount importance to Caltrans, resulting in a continuing effort to improve the operating vehicle fleet. The potential safety changes that are the focus of this project are those that involve safety equipment enhancement over and above the original specifications for the vehicle or outside of the scope of the original equipment design or purpose, such as rear view backup video cameras. The motivation for this project was Division of Equipment (DOE) managers' need for an objective strategy to address safety equipment deployment...

Attributable risk of alcohol and other drugs for crashes in the transit industry

Cunradi, Carol B.
Ragland, David R.
Greiner, Birgit A.
Klein, M.
Fisher, June M.
2005

Objective: To estimate the impact of employee alcohol and drug use on crashes in the transit industry from 1995–2000.

Design: Secondary analysis of federally mandated post crash and random alcohol and drug testing results.

Setting: The US transit industry.

Subjects: Transit industry employees.

Main outcome measures: Relative risk (RR), population attributable risk (PAR), and population attributable risk percentage (PAR%).

Results: For alcohol testing, the estimated PAR% ranged...

Physical workload, ergonomic problems, and incidence of low back injury: A 7.5-year prospective study of San Francisco transit operators

Krause, Niklas
Rugulies, Reiner
Ragland, David R.
Syme, S. Leonard
2004

Background: The etiologic role of biomechanical factors for low back injury (LBI) needs to be confirmed in prospective studies that control for psychosocial factors.

Methods: Complete baseline information on 1,233 vehicle operators was gathered during medical examinations and by questionnaire. First LBI during 7.5 years of follow-up was ascertained from insurance records. Hazard ratios and etiologic fractions were analyzed with Cox regression models stratified by injury severity and controlling for age, sex, height, weight, ethnicity, and biomechanical and...

On The Legal Deterrence Of Pedestrian Hit-and-Run Collisions

Grembek, Offer
Griswold, Julia B.
2012

Hit-and-run collisions—those in which a driver involved in the collision leaves the scene before the arrival of law enforcement officials—are a unique type of traffic violation because the driver's decision is a question of damage control rather than damage prevention. To reduce hitand-run violations, individual state laws impose legal sanctions to deter drivers from leaving the collision scene prematurely. Deterrence Theory dictates that compliance with laws is associated with the certainty, severity, and swiftness of punishment. The purpose of this study is to explore the deterrent...

Safety Evaluation of High-Occupancy Vehicle (HOV) Facilities in California

Ragland, David R.
Oh, Soonmi
Chan, Ching-Yao
2008

This report documents findings from analysis of traffic collision data from sites that display high collision rates only under wet pavement conditions. These sites were selected using Caltrans safety engineers’ field reports, Wet Table C “investigation required” locations, and a new approach called Continuous Risk Profile (CRP). The geometric features at the sites were studied via field visits and review of as-built plans. Rapid spatial changes (i.e., vertical and horizontal curve in short distance), narrower lane width, lack of median, and wider total freeway width were some of the...

Crosswalk Confusion: More Evidence Why Pedestrian and Driver Knowledge of the Vehicle Code Should Not Be Assumed

Mitman, Meghan F.
Ragland, David R.
2014

Traffic safety researchers have long argued that driver behavior outweighs physical elements (such as road design) as a causal factor in motor vehicle collisions. A fundamental causal component of pedestrian—vehicle collisions is also behavior: that of the driver and that of the pedestrian. One determinant of this behavior may be whether the driver, the pedestrian, or both understand the motor vehicle code, which demarcates the right-of-way in pedestrian-vehicle interactions. That is, inappropriate or unlawful behavior may occur because the law is not understood or is misunderstood....

Spatiotemporal Analysis of Macroscopic Patterns of Urbanization and Traffic Safety: A Case Study in Sacramento County, California

Sanghyeok, Kang
Spiller, Margot
Jang, Kitae
Bigham, John M.
Seo, Jongwon
2012

This study provides a preliminary investigation into the relationship between urbanization and trafficcollisions by analyzing the spatial patterns in Sacramento County, California from 1998 to 2008 using urban land classifications and traffic collision data. The ArcGIS directional distribution tool was used to create standard deviational ellipses to investigate the distributional trend of urban land and traffic collisions over time. Statistical outputs representing changes of geographical centroids, elliptical areas, and standard distances (long and short axes) were then...