Data collection

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.

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.

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.


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.


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.

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.

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...

Physical Environments Influencing Bicyclists’ Perception of Comfort on Separated and On-Street Bicycle Facilities

Li, Zhibin
Wang, Wei
Liu, Pan
Ragland, David R.

This study investigates the impacts of physical environments on bicyclists’ perceptions of comfort on separated and on-street bicycle facilities. Based on a field investigation conducted in Nanjing, China, we find that physical environmental factors significantly influencing bicyclists’ perception of comfort on the two types of facility. Cyclists’ comfort is mainly influenced by the road geometry and surrounding conditions on physically separated paths while they pay attention to the effective riding space and traffic situations on on-street bicycle lanes.

The Relative Vulnerability Index: A Framework for Evaluating Multimodal Traffic Safety

Grembek, Offer

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...

Bicycle Commuting Market Analysis Using Attitudinal Market Segmentation Approach

Li, Zhibin
Wang, Wei
Yang, Chen
Ragland, David R.

The market segmentation analysis for bicycle commuting can help identify distinct bicycle market segments and develop specific policies or strategies for increasing the bicycle usage in each segment. This study aims to use the approach of attitudinal market segmentation for identifying the potential markets of bicycle commuting. To achieve the research objective, the household survey is conducted to obtain the travelers’ attitudes towards their commuting travels. The factor analysis is used to explore the latent attitudes. The structural equation modeling (SEM) simultaneously estimates the...

Classification of Bicycle Traffic Patterns in Five North American Cities

Miranda-Moreno, Luis
Nosal, Thomas
Schneider, Robert J.
Proulx, Frank R.

This paper analyses bicycle ridership patterns using a unique database of automated bicycle counts from approximately 40 locations in five North American cities and along the Route Verte in Quebec. The cities involved in this study are Montreal, Ottawa, Portland, San Francisco, and Vancouver. Count data show that the bicycle volume patterns at each location can be classified as utilitarian, mixed utilitarian, recreational and mixed recreational. Study locations classified into each of these categories are found to have consistent hourly and weekly traffic patterns, despite important...