Data

Assessing the Variation of Curbside Safety at the City Block Level

Medury, Aditya PhD
Vlachogiannis, Dimitris
Grembek, Offer, PhD
2020

Investigating the dynamics behind the likelihood of vehicle crashes has been a focal research point in the transportationsafety field for many years. However, the abundance of data in today's world generates opportunities for deepercomprehension of the various parameters affecting crash frequency. This study incorporates data from many differentsources including geocoded police-reported crash data, curbside infrastructure data and socio-demographic data for thecity of San Francisco, CA. Findings revealed that the GFMNB model provides a better statistical fit than the FMNB andNB model in...

Traffic Injury on Tribal Lands in California

Ragland, David, PhD, MPH
Bigham, John
Oum, Sang Hyouk
Chen, Katherine
Felschundneff, Grace
2014

There is a disproportional risk of motor vehicle death and injury among American Indian/Alaska Native (AI/AN) populations in the United States. As home to the nation’s largest population of AI individuals, it is vital that California develop a better understanding of the factors contributing to this risk to guide the development and implementation of interventions to improve traffic safety for this population on the nearly 100 Rancherias and reservations in the state. However, there is very little data about the numbers and types of collisions, and driver and environmental factors...

Evaluation of Injury Severity Updates in California Collision Data

Bigham, John
Oum, Sang Hyouk
2018

Fatal or injury collisions in California must be reported to the California Highway Patrol (CHP) for inclusion in the Statewide Integrated Traffic Records System (SWITRS). After records have been entered into SWITRS they are made publicly available and are accessible through the CHP’s report and data retrieval site called I-SWITRS. However, records accessed in SWITRS are considered provisional and can be updated several years after initial entry. This includes the injury severity level of collisions. If the collision data was accessed prior to an injury severity update, the agency...

Low Income Childhood Pedestrian Injury: Understanding the Disparate Risk

Johnson, Emily
Geyer, Judy A
Rai, Nirmeet
Ragland, David R
2004

A leading cause of death and injury to children is being struck by a motor vehicle. A disproportionate number of injured child pedestrians are of low socioeconomic status. The relationship between socioeconomic status and pedestrian injury is poorly understood. The existing literature is limited by the lack of pedestrian exposure data, a common measure of risk, and a clear conceptual framework for the interaction between socioeconomic status and pedestrian injury. Another issue is the limited availability of injury data. This paper proposes a model for understanding child pedestrian...

The Analysis of Right-of-way for different road users in China: Passing-Passenger-Unit Versus Passenger-Car-Unit

Xiong, Wen, Professor
Zhang, Yuanyuan, PhD
Chen, Xiaohong, Professor
Jiang, Chao
2014

Being a public resource, the roadway space was distributed between different road users based on the Passenger-Car-Unit (PCU) concept. However, this concept tends to under estimate the capacity of public transportation and non-motorized travel. To improve the traditional car-oriented design to become more human-oriented, this study proposed a Passing-passenger-unit (PPU) and the method to observe the PPU in roadway level and area level. The PPU data were collected for urban arterials and residential areas in China to test the method and to compare the right-of-way distribution at different...

HOV Lane Configurations and Safety Performance of California Freeways – An Investigation of Differential Distributions and Statistical Analysis

Jang, Kitae
Chan, Ching-Yao
2009

From a recent study of safety evaluation of HOV-equipped freeways, it was found that limited-access HOV lanes appear to have a safety performance disadvantage when measured by collision distribution or collision rates for the HOV lane alone and for the HOV and left lanes combined. This paper describes the work performed to verify the statistical significance of related findings. Several statistical tests were used: empirical cumulative density function (CDF), Kolmogorov-Smirnov Tests, and comparison of means based on Poisson Distributed Samples. The conclusion that continuous-access HOV...

San Francisco PedSafe II Project Outcomes and Lessons Learned

Hua, Jenna
Gutierrez, Nicolas
Banerjee, Ipsita
Markowitz, Frank
Ragland, David R
2009

This paper presents the project outcomes and lessons learned from the San Francisco PedSafe, a comprehensive pedestrian safety planning and engineering project funded by the Federal Highway Administration. It assesses the effectiveness of the Phase I pedestrian safety plan targeted to higher-injury areas by evaluating the Phase II implementation of a range of mostly low-to-moderate-cost innovative safety improvements.A total of 13 countermeasures (comprised of nine general engineering countermeasures and four Intelligent Transportation Systems (ITS) countermeasures) were implemented by the...

The relative vulnerability index: a framework for evaluating multimodal traffic safety

Grembek, Offer
2012

The multimodal transportation network includes a mix of inherently different modes. In addition to differences in price, range, and comfort of travel, these modes differ in mass and velocity, which correspond to different orders of magnitude in the kinetic energy carried. This discrepancy in kinetic energy affects both the level of protection of each mode, and the level of damage it can inflict on users of other modes. Unfortunately, accounting for both sides of a crash is often overlooked. While the quantities and variables of collected data continue to increase, the analyses conducted...

Missed or Delayed Medical Care Appointments by Older Users of Nonemergency Medical Transportation Services

MacLeod, Kara E.
Ragland, David R.
Prohaska, Thomas R.
Irmiter, Cheryl Irmiter
Satariano, William
Leary, Mary A.
2012

Non-emergency medical transportation (NEMT) can prevent emergency care as a result of delayed or missed medical appointments. Medicaid provides NEMT for low income individuals who have no other means of transportation and this is a critical component of the health care delivery system. This study examined cancelled trips in Medicaid adults age 65+ to explore whether barriers persist for a growing segment of the population who face particular challenges of age-related declines in health and function. Multivariate logistic regression analyses were conducted using transportation brokerage...

Emergency Medical Services (EMS) and the California EMS Information System (CEMSIS) Working Paper

Doggett, Sarah
Ragland, David R.
Felschundneff, Grace
2019

This study examines data from the California EMS Information System (CEMSIS) to identify factors that influence prehospital time for EMS events related to motor vehicle collisions (MVCs). While only 19 percent of the United States population resides in rural areas, over half of all traffic fatalities involve rural motor vehicle collisions. Rural and urban MVCs result in similar injury severities, however relative inaccessibility of trauma centers and prehospital EMS time (activation, response, and transport time) likely contribute to the generally higher mortality rate in rural areas. For...