SafeTREC

Pedestrian and Bicycle Safety Evaluation for the City of Emeryville at Four Intersections

Johnson, Emily S.
Ragland, David R
Cooper, Jill F
O'Connor, Terri
2005

The City of Emeryville is small in area (1.2 square miles) and population (7,000), but it is one of the most regionally connected cities in the Bay Area (California). Emeryville is situated at the eastern end of the San Francisco-Oakland Bay Bridge, contains the intersection of Interstate Highway 80 (I-80) with several regional and other interstate highways, and has extensive transportation access by Amtrak Rail, Alameda County (AC) Transit and heavy cargo facilities at the nearby Port of Oakland. The city has many large employers and several large shopping areas, and the daytime...

Safety Performance of High-Occupancy Vehicle (HOV) Facilities: Evaluation of HOV Lane Configurations in California

Jang, Kitae
Chung, Koohong
Ragland, David R.
Chan, Ching-Yao
2009

Collision data from High Occupancy Vehicle (HOV) facilities with two different types of access, continuous and limited, are examined in this paper. The findings show that HOV facilities with limited access offer no safety advantages over those with a continuous access. Compared with continuous access HOV lanes, a higher percentage of collisions was concentrated on limited access HOV lanes. Limited access HOV lanes also had higher collision rates. Findings from investigating the relationship between collision rates in HOV lanes with respect to shoulder width, length of access, and the...

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

Bigham, John
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 system....

Prehospital Response Time and Traumatic Injury—A Review

Doggett, Sarah
Ragland, David R.
Felschundneff, Grace
2018

A significant proportion of fatalities from motor vehicle collisions (MVC) could be prevented through better emergency medical service (EMS) care. Despite a lack of conclusive research, there is a consensus that prehospital time (the time between the MVC and the patient’s arrival at the hospital) must be reduced as much as possible. Many studies use response time (the time between EMS dispatch and arrival at the scene) as an indicator of overall prehospital time and a metric of EMS performance. However, there are other components of prehospital time that may be equally important, including...

False Alarms and Human-Machine Warning Systems

Zabyshny, Aleksandr A
Ragland, David R
2003

This work illustrates that false alarms are likely to have significant frequencies as well as detrimental influence on the effectiveness of human-machine warning systems. Several factors are responsible for false alarm materialization, including the need to predict uncertain conditions in the future, variability of human perception, and low a priori probabilities of traffic collisions. The effect of false alarms on human trust in warning systems and on credibility of warnings could be considerable even for low false alarm rates. One way to decrease false alarm rates would be to focus on...

Property Damage Crash Equivalency Factors for Solving the Crash Frequency-Severity Dilemma: Case Study on South Korean Rural Roads

Oh, Jutaek
Washington, Simon
Lee, Dongmin
2010

Safety interventions (e.g. median barriers, photo enforcement) and road features (e.g. median type and width) can influence crash severities, crash frequencies, or both. Both dimensions—crash frequency and crash severity—are needed to obtain a full accounting of road safety. Extensive literature and common sense both dictate that all crashes are not ‘created’ equal—with fatalities costing society more than 1000 times the cost of property damage only crashes. Despite this glowing disparity, the profession has not unanimously embraced or successfully defended a non-arbitrary severity...

Evaluation of Traffic and Environment Effects on Skid Resistance in California

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

Skid resistance is one of the important serviceability indicators related to safety on wet pavements. There is a need to manage skid resistance systematically to maintain the level of safety performance of roadway surfaces. This study focused on the development of a skid resistance deterioration model based on the analysis of skid data inventory collected in California. The California Department of Transportation (Caltrans) has collected skid resistance data across the complete state highway network over the past two decades using a standard locked-wheel skid trailer, ASTM E-274. This...

Factors Associated with Hit-and-Run Pedestrian Fatalities and Driver Identification

MacLeod, Kara E.
Griswold, Julia
Arnold, Lindsay S.
Ragland, David R.
2010

Because hit-and-run crashes account for a significant share of pedestrian fatalities, a better understanding of these crashes will assist efforts to reduce pedestrian fatalities. Of the more than 48,000 pedestrian deaths that were recorded in the United States between 1998 and 2007 (Fatality Accident Reporting System [FARS]), 18.1% of them were the victims of hit-and-run crashes, and the percentage of fatal pedestrian hit-and-runs has been rising as the number of all pedestrian fatalities has decreased. Using FARS data on single pedestrian fatal victim crashes between 1998-2007, logistic...

Association between Roadway Intersection Characteristics and Pedestrian Crash Risk in Alameda County, California

Schneider, Robert J.
Diogenes, Mara Chagas
Arnold, Lindsay S.
Attaset, Vanvisa
Griswold, Julia
Ragland, David R.
2010

Each year from 1998 to 2007, an average of approximately 4,800 pedestrians were killed and 71,000 pedestrians were injured in United States traffic crashes. Because many pedestrian crashes occur at roadway intersections, it is important to understand the intersection characteristics that are associated with pedestrian crash risk. This study uses detailed pedestrian crash data and pedestrian volume estimates to analyze pedestrian crash risk at 81 intersections along arterial and collector roadways in Alameda County, California. The analysis compares pedestrian crash rates (crashes per 10,...

HOV Lane Configurations and Collision Distribution on Freeway Lanes – An Investigation of Historical Collision Data in California

Chung, Koohong
Chan, Ching-Yao
Jang, Kitae
Ragland, David R.
Kim, Yong Hee
2007

High-Occupancy Vehicle (HOV) lane programs are widely adopted in metropolitan areas in an effort to reduce congestion by encouraging carpooling. However, the operation of HOV lanes may result in traffic interactions that affect safety performance. In this paper, historical data from a number of freeway corridors in California are used to illustrate the distribution of collisions on different lanes on the freeway. The peak hours’ data, when compared to those in the non-peak hours, from all corridors indicate that more interactions due to traffic weaving near the HOV lanes might lead to a...