Roads/Highways

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...

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...

Driver Behavior at Rail Crossings: Cost-Effective Improvements to Increase Driver Safety at Public At-Grade Rail-Highway Crossings in California

Cooper, Douglas L.
Ragland, David R
2007

This report examines conditions affecting vehicle-train collisions at rail crossings in California, and recommends effective countermeasures and implementation strategies. In doing so, the report helps meet California’s goal of efficiently utilizing state and federal funding available through SAFETEA-LU for increasing the safety at public at grade rail-highway crossings.

Intersection Decision Support Project: Taxonomy of Crossing-Path Crashes at Intersections Using GES 2000 Data

Ragland, David R.
Zabyshny, Aleksandr A.
2003

The Intersection Decision Support (IDS) Project is designed to reduce crossing-path (CP) crashes at intersections by providing crucial information to drivers that would help them avoid such crashes. Over the past decade, researchers have used the General Estimates System (GES, a representative sample of police-reported crashes in the US) and other data sources to develop a taxonomy of CP crashes and pre-crash scenarios as groundwork for crash-prevention efforts. The current study builds on and extends prior work by constructing a taxonomy of CP crashes using data from the 2000 GES and...

Develop a Plan to Collect Pedestrian Infrastructure and Volume Data for Future Incorporation into Caltrans Accident Surveillance and Analysis System Database

Zhang, Yuanyuan
Proulx, Frank R.
Ragland, David R.
Schneider, Robert J.
Grembek, Offer
2014

This project evaluates the feasibility of developing a pedestrian and bicycle infrastructure database and volume database for the California state highway system. While Caltrans currently maintains such data for motor vehicles in the Traffic Accident Surveillance and Analysis System - Transportation System Network (TASAS-TSN) database, the agency does not keep records on pedestrian or bicycle facilities. This information is crucial for improving the safety of these vulnerable road users. This project developed a proposed database structure and corresponding data collection methodology. It...

Advancing Road User Charge (RUC) Models in California: Understanding Social Equity and Travel Behavior Impacts

Lazarus, Jessica
Broader, Jacquelyn
Cohen, Adam
Bayen, Alexander, PhD
Shaheen, Susan, PhD
2022

The State of California is currently moving forward with a road usage charge (RUC) demonstration program, creating promising research opportunities to examine the potential social equity implications of a shift from a gas tax to a RUC system in California. RUC . To this aim, this study investigates the relative burden of gas taxes and mileage-based RUC across various sociodemographic and geographic dimensions by examining key trends in road use, vehicle ownership, fuel consumption, use of RUC-related technologies, and attitudes/opinions related to RUC adoption. Expert interviews were...

Hybrid Traffic Data Collection Roadmap: Objectives and Methods

Bayen, Alexander
Sharafsaleh, Mohammad
Patire, Anthony D.
2013

Traffic data is used to estimate current traffic conditions so that travelers and agencies can make better decisions about how to use and manage the transportation network. This research explores the fusion of probe data (vehicle speed and direction) with loop data (density, speed, and count) in the context of producing overall network speed and travel time estimates. Speed and travel time estimates are useful in many circumstances, but current system control strategies (ramp metering, for example) require density data. While it is difficult to significantly increase the quantity of loop...