Data collection

A behavioral modeling approach to bicycle level of service

Griswold, Julia B.
Yu, Mengqiao
Victoria Filingeri
Grembek, Offer
Joan Walker
2018

Bicycle level of service (LOS) measures are essential tools for transportation agencies to monitor and prioritize improvements to infrastructure for cyclists. While it is apparent that different types of cyclists have varying preferences for the facilities on which they ride, in current research and practice, measures are used that are either insufficiently quantitative and empirical or lack cyclist segmentation. In this study, we conducted a detailed survey on cyclist habits, preferences, and user experience, capturing responses to videos of a bicycle traveling on road segments in the San...

Visualizing Teen Driver Safety Needs: SafeTREC researchers present at 2017 GIS Day

November 10, 2017

Teen Heat Map Presentation

State Superintendent of Public Instruction, Tom Torlakson, with staff from the California Department of Education, California Office of Traffic Safety and SafeTREC.

On November 2, 2017, SafeTREC co-director Jill Cooper and researchers SangHyouk Oum and Liwei Fu presented SafeTREC’s latest data and mapping analysis tool, the Teen Safety Heat Map at the 2017 Geographic Information Systems...

Observational Study of Cell Phone and Texting Use Among California Drivers 2012 and Comparison to 2011 Data

Cooper, Jill F.
Ragland, David R.
Ewald, Katrin
Wasserman, Lisa
Murphy, Christopher J.
2013

This methodological report describes survey research and data collection methods employed for the second Observational Survey of Cell Phone and Texting Use among California Drivers study conducted in 2012. This study was conducted by Ewald & Wasserman Research Consultants (E&W) on behalf of the California Office of Traffic Safety and the Safe Transportation Research and Education Center at University of California at Berkeley. The survey’s goal was to obtain a statewide statistically representative observational sample of California’s cell phone use behaviors, focusing on...

Novelty helmet use and motorcycle rider fatality

Rice, Thomas M.
Troszak, Lara
Erhardt, Taryn
Trent, Roger B.
Zhu, Motao
2017

OBJECTIVES:

To compare the risk of fatal injury across helmet types among collision-involved motorcyclists.

METHODS:

We used data from a cohort of motorcyclists involved in police-reported traffic collisions. Eighty-four law enforcement agencies in California collected detailed information on helmet and rider characteristics during collision investigations in June 2012 through July 2013. Multiply-adjusted risk ratios were estimated with log-binomial regression.

RESULTS:

The adjusted fatal injury risk ratio for novelty helmets was 1.95 (95% CI 1.11-3.40, p...

Report Pedestrian and Bike Safety Issues in the Bay Area

August 24, 2017

Crowdsourced data of bike and safety issues

As a bicyclist or pedestrian, have you been hit or almost hit by a car, truck, motorcycle or bicycle? Do you generally feel unsafe when biking/walking in The Bay Area? Report pedestrian and bike safety issues for one month for a chance to win a gift card and help city officials and researchers understand how to use crowdsourced data to address safety...

Drinking and driving and perceptions of arrest risk among California drivers: Relationships with DUI arrests in their city of residence

MacLeod, Kara E.
Karriker-Jaffe, Katherine J.
Satariano, William A.
Kelley-Baker, Tara
Lacey, John H.
Ragland, David R.
2017

Objective: Addressing drinking and driving remains a challenge in the United States. The present study aims to provide feedback on driving under the influence (DUI) in California by assessing whether drinking and driving behavior is associated with the DUI arrest rates in the city in which the driver lives; whether this is due to perceptions that one can get arrested for this behavior; and whether this differed by those drivers who would be most affected by deterrence efforts (those most likely to drink outside the home).

Methods: This study consisted of a 2012 roadside survey of 1,...

The Association between Booster Seat Use and Risk of Death Among Motor Vehicle Occupants aged 4–8: A Matched Cohort Study

Rice, Thomas M.
Anderson, Craig L.
Lee, A. S.
2009

Objective: To estimate the effectiveness of booster seats and of seatbelts in reducing the risk of child death during traffic collisions and to examine possible effect modification by various collision and vehicle characteristics.

Methods: A matched cohort study was conducted using data from the Fatality Analysis Reporting System. Death risk ratios were estimated with conditional Poisson regression, bootstrapped coefficient standard errors, and multiply imputed missing values using chained equations.

Results: Estimated death risk ratios for booster seats used with seatbelts...

Geocoding Police Collision Report Data from California: A Comprehensive Approach

Bigham, John M.
Rice, Thomas M.
Pande, Swati
Lee, Junhak
Park, Shin Hyoung
Gutierrez, Nicolas
Ragland, David R.
2009

Background

Collision geocoding is the process of assigning geographic descriptors, usually latitude and longitude coordinates, to a traffic collision record. On California police reports, relative collision location is recorded using a highway postmile marker or a street intersection. The objective of this study was to create a geocoded database of all police-reported, fatal and severe injury collisions in the California Statewide Integrated Traffic Records System (SWITRS) for years 1997-2006 for use by public agencies.

Results

Geocoding was completed with a multi-step...

The Inclusion of Adult Vehicle Occupants in Matched Cohort Studies of Child Restraint Effectiveness: A Study of Potential Bias

Rice, Thomas M.
Anderson, Craig L.
2010

Objective: To determine whether either the inclusion of adults in matched cohort studies of passenger vehicle occupants or modification of age effects by collision severity biases child restraint risk ratios biases estimate of child restraint effectiveness.

Methods: Monte Carlo data simulations were conducted to represent 10,000 collision-involved vehicles carrying a mix of children and adults. The effects of age category, adult seat belt use, child seat belt use, and child safety seat use were set to known values. Age was a modifier of the adult and child seat belt risk ratios and...

Bicycle Infrastructure that Extends beyond the Door: Examining Investments in Bicycle-oriented Design through a Qualitative Survey of Commercial Building Owners and Tenants

Orrick, Phyllis
Frick, Karen Trapenberg
Ragland, David R.
2011

This paper presents the results of a qualitative survey of commercial owners, managers, and occupants in the City of Berkeley who have invested in on-site bicycle facilities such as secure parking, showers, changing rooms, and clothing lockers, what we are calling “bicycle-oriented design” (BOD). The sites represent a selection of building types common in the commercial building stock in U.S. cities. The research is designed to answer three questions about the use of BOD: (1) what were motivations behind the decision to invest in BOD (2) what are the challenges and rewards for...