Data

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...

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...

Simulation Techniques to Obtain Confidence Intervals for Willingness to Pay Measures

Espino, Raquel
Ortuzar, Juan de Dios
Roman, Concepcion
2004

We obtain confidence intervals for willingness-to-pay (WTP) measures derived from a mode choice model estimated to analyse travel demand for suburban trips in the two main interurban corridors in Gran Canaria island, using a mixed RP/SP data base. We considered a specification of the systematic utility that incorporates income effect and interactions among socioeconomic variables and level-of-service attributes, as well as between travel cost and frequency. As our model provides rather complex expressions of the marginal utilities, we simulated the distribution of the WTP (in general,...

Improved Data Measurement Using Existing Loop Detectors

Coifman, Benjamin
1999

This paper develops an improved algorithm for estimating velocity from isolated loop detector data. Unlike preceding works, the algorithm is simple enough that it can be implemented using existing controller hardware. The discussion shows how the benefits of this work extend to automated tests of detector data quality at dual loop speed traps. Finally, this paper refutes an earlier study that found conventional isolated loop velocity estimates are biased keywords: traffic surveillance, single loop detectors, velocity estimation data screening

A Five-Year Development Plan for the California Aviation Database

Tsao, H.-S. Jacob
1999

The California Aviation Database (CAvD) project was suggested by Caltrans Aeronautics Program to fulfill a need of the planners involved in aviation system planning and programming activities to locate and access aviation data and information in an efficient and comprehensive way. CAvD is being implemented in the form of an Internet website and is currently intended as a five-year project. However, the development can be accelerated, and the duration will depend on the available resources. CAvD is a joint project between the National Center of Excellence for Aviation Operations Research(...

Welfare Analysis of Informal Transit Services in Brazil and the Effects of Regulation

Golub, Aaron David
2003

In Brazil, the recent explosion of informal transport activity is having profound effects on formal, regulated transport systems and is the source of great controversy in the urban passenger transportation arena. A variety of policies are being proposed to manage what has been an uncontrolled growth of the sector. This study seeks to understand the advantages these systems have for users who choose them, and how proposed policies will impact these benefits. A corridor in Rio de Janeiro with substantial informal activity was used as a case study and field trips were made to gather basic...

Where the Crosswalk Ends: Mapping Crosswalk Coverage via Satellite Imagery in San Francisco

Moran, Marcel E.
2022

Marked crosswalks are the primary means of safeguarding pedestrian travel at intersections in American cities. In the face of decades-high pedestrian fatalities nationwide, the provision of adequate cross walks is highly salient. Though, how they are spatially distributed across an entire city, and vary by neighborhood, has drawn little academic scrutiny. Given that, this study utilizes satellite imagery to map the presence of marked crosswalks throughout San Francisco, a dense, walkable city that has struggled to reach its pedestrian-safety goals. For the first time, this allows for a...

Smartphone Applications and Data Impacting Transportation

Shaheen, Susan, PhD
Cohen, Adam
2018

Demographic shifts, improvements in computing power and mapping technology, the use of cloud computing, and changes in wireless communication —coupled with the growth of data availability and data sharing —are changing the way people travel. Increasingly, mobility consumers are turning to smartphone “apps” for a wide array of transportation activities including: vehicle routing, real-time data on congestion, information regarding roadway incidents and construction, parking availability, and real-time transit arrival predictions. Travel time savings (e.g., high occupancy vehicle lanes...

Equity and Shared Mobility

Shaheen, Susan, PhD
Cohen, Adam
2018

Ensuring equal access for protected classes impacted by shared mobility services is critical. In California, this can include provisions mandating access for individuals with disabilities, as well as prohibitions in discrimination against other protected classes. Many of these laws not only prohibit discrimination against the end user but also shared mobility employees. In addition to prohibiting discrimination, it is imperative to ensure shared mobility is accessible to all. Equitable treatment of shared mobility providers (e.g., data, insurance, licensing) is also a key consideration.