Environment

Cooperative Multiple-Sensor Fusion for Automated Vehicle Control

Hedrick, J. K.
Jang, J.
Potier, A.
2004

The number and quality of sensors available for both on-board vehicle and infrastructure-based sensing is increasing while the cost of these sensors is rapidly decreasing. On-board vehicle sensors can be utilized for both individual vehicle safety as well as automated vehicle control. It is becoming imperative that "fusion" techniques be developed, i.e., methods to combine the wide variety of sensors available so that reliable and accurate information can be obtained even though individual sensors may fail or become extremely noisy. The process of sensor fusion combines multiple sensor...

Planning the Development of a Commercial Motor Vehicle Virtual Weigh Station Technology Testbed

Miller, Mark A.
Sharafsaleh, Ashkan
2010

This report describes the issues associated with planning the development of a technology testbed for Virtual Weigh Stations in California. These issues may be organized into the following categories: system design and architecture, operational environment, siting & location, data collection, functional requirements and options, technology requirements and options, identification  of  stakeholders,  operational  testing  and  evaluation  (operational  scenarios,  performance measures, benefits &amp...

Sensor-Friendly Freeways: Investigation of Progressive Roadway Changes to Facilitate Deployment of AHS

Misener, James A.
Griffiths, Paul
Johnson, Lee
Segal, Andy
2001

Intelligent "driver assistance" systems which utilize in-vehicle forward-looking sensors can be supplemented by vehicle-vehicle and vehicle-highway cooperative elements to comprise a "sensor-friendly" highway environment that would enhance the operational efficiency, and ultimately, the safety benefits of these systems. In our research, we have identified the current limitations of autonomous sensing systems in target/background discrimination with cluttered highways. Based upon this, and by limiting ourselves to "sensed" (and not wireless) systems, we have conceived relatively inexpensive...

Evaluation of Wet Weather Accident Causation Criteria

Oh, Soon Mi, MS
Ragland, David R., PhD
Chan, Ching-Yao, PhD
2010

This report documents findings from analysis of traffic collision data from sites that display high collision rates only under wet pavement conditions. These sites were selected using Caltrans safety engineers’ field reports, Wet Table C “investigation required” locations, and a new approach called Continuous Risk Profile (CRP).The geometric features at the sites were studied via field visits and review of as-built plans. Rapid spatial changes (i.e., vertical and horizontal curve in short distance), narrower lane width, lack of median, and wider total freeway width were some of the notable...

Environmental Impacts of Transportation Network Company (TNC)/Ride-Hailing Services: Evaluating Net Vehicle Miles Traveled and Greenhouse Gas Emission Impacts within San Francisco, Los Angeles, and Washington, D.C. Using Survey and Activity Data

Martin, Elliot
Shaheen, Susan
Wolfe, Brooke
2024

Transportation Network Companies (TNCs) play a prominent role in mobility within cities across the globe. However, their activity has impacts on vehicle miles traveled (VMT) and greenhouse gas (GHG) emissions. This study quantifies the change in personal vehicle ownership and total miles driven by TNC drivers in three metropolitan areas: San Francisco, CA; Los Angeles, CA; and Washington, D.C. The data sources for this analysis comprise two surveys, one for TNC passengers (N = 8630) and one for TNC drivers (N = 5034), in addition to data provided by the TNC operators Uber and Lyft. The...

Integrated Roadway/Adaptive Cruise Control System: Safety, Performance, Environmental and Near Term Deployment Considerations

Ioannou, Petros
Wang, Yun
Chang, Hwan
2007

In this project, we present the design, analysis and performance evaluation of the Integrated Roadway/Adaptive Cruise Control System (IRAC) proposed in Task Order (TO) 4242 and studied further in the continuation of TO4242 under TO5501. The IRAC system is a highway traffic control system which integrates ramp metering strategies and a speed control strategy by taking into account highway to vehicle communication, and adaptive cruise control (ACC) system technologies on board of the vehicles. The IRAC system closes the loop of an almost open loop highway traffic system by controlling both...

Evaluation Methodologies for ITS Applications

Gillen, David
Li, Jianling
1999

California’s Transportation Plan [CTP] was designed to set the course for the future of transportation in California.’ At the heart of the plan are three comprehensive policies; promoting the economic vitality of California by assuring mobility and access for people, goods, services and information, provide safe, convenient and reliable transportation and, provide environmental protection and energy efficiency. The Caltrans Strategic Plan in keeping with the CTP creates a vision of a balanced, integrated multimodal transportation network to move people, goods, services and information...

Institutional, Organizational and Market Aspects of Successful ITS Deployment: A Case Study Analysis

Conroy, Patrick
2003

This research follows on a previous study to explore key aspects of successful Intelligent Transportation Systems (ITS) deployment within existing institutional, organizational and market environments. The researcher developed three additional case studies of successful ITS deployment in the U.S. and Europe, and revisited one case from the previous work. Results from literature searches and surveys were analyzed, and findings on institutional, organizational and market factors are presented. Key words: ITS, deployment, institutional, value, business models, benefits, highway capacity

Integrated Traffic and Communications Modeling Environment for ATMIS

Varaiya, P.
Walrand, J.
Wu, F.F.
Polydoros, A.
Sylvester, J.
1997

The aims of this MOU were to create an integrated environment for modeling traffic flow, sensor data, and the communications infrastructure for ATMIS. The research plan was to build separate tools for measuring the communications requirements of ATMIS traffic, modeling a mobile radio communications environment, and communications network design, and then to integrate them in an object-oriented environment from which one could also access existing or new road traffic simulation packages.Section 1 of the report presents a framework for estimating the vehicle-roadside communications...

Driving Intelligence Replacement in a Decision-Oriented Deployment Framework for Driving Automation

Tsao, H.-S. Jacob
Ran, Bin
1996

What some human drivers have done wrong has been blamed for much of the problem associated with the current highway systems. For example, driver inattention, fatigue and other human errors have often been cited as major sources of safety hazard on current highways and human capabilities as major limitations on current highway capacity. Such human deficiencies and the pervasive urban traffic congestion have motivated the concept of Automated Highway Systems (AHS). The fundamental objective of AHS is to achieve user and societal benefits through replacing human driving by automated machine...