Road User Behavior

Impacts of Pedestrians on Capacity and Delay of Major Street Through Traffic at Two-Way Stop-Controlled Intersections

Yang, Zhao
Zhang, Yuanyuan
Zhu, Renwei
Ye, Xiaofei
Jiang, Xiaohong
2014

This paper aims to estimate the impacts of pedestrians on capacity and average control delay for the major street through traffic at two-way stop-controlled (TWSC) intersections. A procedure was proposed to estimate the expected delay for major street through vehicles based on the pedestrian arrival time and motorist yielding behavior. Field data were collected to calibrate the crucial parameters in the established models. The proposed models were then validated against field measured data. It was found that the calibrated models provided reasonable delay estimates. Based on the...

Driver obesity and the risk of fatal injury during traffic collisions

Rice, Thomas M.
Zhu, Motao
2016

Background Few studies have looked at how obesity affects injury outcomes among vehicle occupants involved in traffic collisions.

Objective To estimate the association of obesity with death risk among drivers of passenger vehicles aged ≥16 and to examine effect modification by driver sex, driver seat belt use, vehicle type and collision type.

Methods We conducted a matched-pair cohort study using data from the Fatality Analysis Reporting System. WHO body mass index (BMI) categories were calculated. Data were analysed using conditional...

Developing Safety Management Tools for State Departments of Transportation

Chung, Koohong
Grembek, Offer
Lee, Jinwoo
Choi, Keechoo
2013

Two safety management tools have recently been developed for the California Department of Transportation (Caltrans). One is the continuous risk profile (CRP) approach, which is a network screening procedure, and the other is the California Safety Analyst (CASA), a web-based application designed to assist state safety engineers in conducting safety investigations and in documenting their findings. This paper provides a qualitative description of the two tools and summarizes feedback from more than 100 Caltrans safety engineers who attended demonstrations of the web-based application....

Geocoding vehicle collisions on Korean expressways based on postmile referencing

Park, Shin Hyoung
Bigham, John M.
Kho, Seung-Young
Kang, Seungmo
Kim, Dong-Kyu
2011

Geocoding is the process of assigning latitude and longitude coordinates to data that contain spatial information. Geocoded records of motor vehicle collisions are an invaluable resource for injury prevention researchers. The objective of this study is to apply the postmile referencing system for geocoding collisions on Korean expressways and summarize the methodology and results with comparative research efforts in the USA. A street network provided by Korea Expressway Corporation was cleaned and calibrated using ArcGIS and a customized Visual Basic for Applications (VBA) tool....

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...

Using Geographically Weighted Poisson Regression for county-level crash modeling in California

Li, Zhibin
Wang, Wei
Liu, Pan
Bigham, John M.
Ragland, David R.
2013

Development of crash prediction models at the county-level has drawn the interests of state agencies for forecasting the normal level of traffic safety according to a series of countywide characteristics. A common technique for the county-level crash modeling is the generalized linear modeling (GLM) procedure. However, the GLM fails to capture the spatial heterogeneity that exists in the relationship between crash counts and explanatory variables over counties. This study aims to evaluate the use of a Geographically Weighted Poisson Regression (GWPR) to capture these spatially varying...

Promoting Research Results and New Technologies: Making the Case for Accelerated Deployment

Andrews, Stephen
Madanat, Samer
Ragland, David R.
West, Thomas
2011

Deploying innovations in transportation products and services to Stage 5 of the product development process represents a growing challenge for the California Department of Transportation’s (Caltrans) Division of Research and Innovation (DRI). This technical agreement focused on communicating the promise of select products and services through outreach and promotion in an effort to gain broader knowledge, understanding, and acceptance of the innovations leading to their adoption by Caltrans and the transportation community at-large. Attention is given to outreach and promotion of ROSA-CRP...

Visual Assessment of Pedestrian Crashes

Griswold, Julia B.
Fishbain, Barak
Washington, Simon
Ragland, David R.
2010

Of the numerous factors that play a role in fatal pedestrian collisions, the time of day, day of the week, and time of year can be significant determinants. More than 60% of all pedestrian collisions in 2007 occurred at night, despite the presumed decrease in both pedestrian and automobile exposure during the night. Although this trend is partially explained by factors such as fatigue and alcohol consumption, prior analysis of the Fatality Analysis Reporting System database suggests that pedestrian fatalities increase as light decreases after controlling for other factors.

This...

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...