Data

A Safe System Approach to Pedestrian High Injury Network Development in Oakland, California

Chen, Angie
2024

As jurisdictions update their High Injury Networks, discrepancies between the initial and updated HINs are to be expected. However, this lack of stability and consistency can negatively impact the prioritization of limited resources. In order to mitigate known issues with crash data underreporting and statistical biases, I examined strategies for utilizing data on underlying roadway characteristics to augment traditional collision analysis. Using the City of Oakland as a case study city, I assessed the stability of the pedestrian High Injury Network across two consecutive five-year periods...

Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System

Abkin, Michael H.
Gilgur, Alexander
Bobick, John C.
Hansman, R. John
Reynolds, Tom G.
Vigeant-Langlois, Laurence
Hansen, Mark
Gosling, Geoffrey D.
Baumgardner, William F.
2002

This report constitutes the final report for Calendar Year 2001 (CY01) under Contract Number NAS2-99072 for the third year of a three-year research project entitled “Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System.” The objective of this research is to investigate and develop techniques to enable NAS fast-time simulation modeling to be useful for conducting safety analysis. The research efforts focus on examining the type of safety issues that could be appropriately modeled by fast-time simulations and developing, testing, and...

Struggling to Connect: Housing and Transportation Challenges of Low-Income Suburban Residents in the San Francisco Bay Area

Pan, Alexandra
Deakin, Elizabeth, PhD
Shaheen, Susan, PhD
2024

Suburban areas have lower density development than urban areas, which may make them less accessible for the growing population of low- and moderate-income suburban residents, particularly those without a personal vehicle. This research examines factors that lead these households to move to suburban areas and identifies accessibility barriers they face. We use a mixed-methods approach with Public Use Microdata Sample (PUMS) data from the U.S. Census, online/in-person surveys (n=208), and interviews conducted in English and Spanish (n=25) with households in Contra Costa County with an income...

Geometry of Vanishing Points and its Application to External Calibration and Realtime Pose Estimation

Kim, ZuWhan
2006

Vanishing points of an image contain important information for camera calibration. Various calibration techniques have been introduced using the properties of vanishing points to find intrinsic and extrinsic calibration parameters. This paper revisits the vanishing points geometry and suggests a simple extrinsic parameter estimation algorithm which uses a single rectangle. The comparison with the Camera Calibration Toolbox for Matlab ® shows that the proposed algorithm is highly competitive. The suggested technique is also applied to a realtime pose estimation for an unmanned air vehicle’s...

Moving Bottlenecks: A Numerical Method that Converges in Flows

Daganzo, Carlos F.
Laval, Jorge A.
2003

This paper presents a numerical method to model kinematic wave (KW) traffic streams containing slow vehicles. The slow vehicles are modeled discretely as moving boundaries that can affect the traffic stream. The proposed scheme converges in flows, densities and speeds without oscillations, and therefore can be readily used in situations where one wishes to model the effect of the traffic stream on the bottlenecks too. The approach is more accurate than Godunov's method in situations where the latter can be applied.

Mobile Device Data Analytics for Next-Generation Traffic Management

Macfarlane, Jane, PhD
Patire, Anthony, PhD
Deodhar, Kanaad
Laurence, Colin
2021

Quality data is critically important for research and policy-making. The availability of device location data carrying rich, detailed information on travel patterns has increased significantly in recent years with the proliferation of personal GPSenabled mobile devices and fleet transponders. However, in its raw form, location data can be inaccurate and contain embedded biases that can skew analyses. This report describes the development of a method to process, clean, and enrich location data. Researchers developed a computational framework for processing large scale location datasets....

Background Paper: The General Transit Feed Specification (GTFS) Makes Trip-Planning Easier — Especially During a Pandemic — Yet its Use by California Agencies is Uneven

Frick, Karen Trapenberg, PhD
Kumar, Tanu, PhD
Post, Alison, PhD
2020

The General Transit Feed Specification (GTFS) is an open source data format public transportation agency use to share information about routes and vehicle arrival and departure times. A variety of trip-planning applications, including Google Maps, rely on GTFS feeds to incorporate public transit information. In April 2020, the California Integrated Travel Project conducted a Feasibility Study that called for the widespread adoption of GTFS-static (GTFS-s) and GTFS-realtime (GTFS-r) to make transit simpler for California residents; however, there is little research on patterns of...

Local Governments Strategies to Improve Shared Micromobility Infrastructure

Shaheen, Susan, PhD
Martin, Elliot, PhD
Cohen, Adam
2024

This brief explores how shared micromobility (bikesharing and scooter sharing) has evolved since the pandemic. Primary data for this report were collected through four surveys: An Operator Survey (n=25) and an Agency Survey (n=52) distributed between January 2022 and May 2022 to all known shared micromobility operators and agencies and included questions about the attributes of shared micromobility systems1 operating within those agency jurisdictions and operator markets; and a similar Operator Survey (n=29) and an Agency Survey (n=52) distributed between January 2023 and June 2023 to all...

Could Transportation Network Companies help Improve Rail Commuting?

Darling, Wesley
Cassidy, Michael J.
2024

Commuter rail is known to have a “first- and last-mile” problem (i.e., a lack of options for getting commuters to and from a rail station). The first- and last-mile dilemma creates inequalities in access. For example, high-income commuters drive to work (forgoing transit altogether), middle-income commuters drive to a rail station and pay to park, and low-income commuters rely on feeder buses or walking to reach a rail station. Transportation network companies (TNCs), like Uber and Lyft, are a viable option for connecting travelers to rail stations, especially for those who don’t own a car...

Development Of System Safety Performance Measures In Support Of The Global Analysis And Information Network

Gosling, Geoffrey
1998

In May 1996, the Federal Aviation Administration (FAA) announced a new and innovative approach to reach the goal of "zero accidents," known as the Global Analysis and Information Network (GAIN). This is envisaged as a privately owned and operated international information infrastructure for the collection, analysis, and dissemination of aviation safety information that would involve the use of a broad variety of worldwide aviation data sources, coupled with comprehensive analytical techniques, to facilitate the identification of existing and emerging aviation safety problems. In support of...