PATH

Aerodynamic Forces on Truck Models, Including Two Trucks in Tandem

Hammache, Mustapha
Michaelian, Mark
Browand, Fred
2001

The present wind tunnel experiment describes 6-component force and moment data measured for both the cab and the trailer of a simplified model truck. Forces and moments are presented in coefficient form. The cab is sufficiently smooth that no flow separation occurs at zero yaw. The trailer has rounded forward vertical edges and sharp upper and lower edges. Both cab and trailer have wheels. The test matrix includes variation of the cab-trailer gap, and the yaw angle between the model plane of symmetry and the axis of the wind tunnel. The yaw angle is meant to account for the presence of an...

Freeway Performance Measurement System (PeMS)

Chen, Chao
2003

The freeway Performance Measurement System (PeMS) collects real time traffic data from sensors and generates performance measures of vehicle miles traveled, hours traveled, and travel time. This project is sponsored by the California Department of Transportation (Caltrans). PeMS provides tools and reports for traffic planners, operators, and engineers. It has a Web interface. Growing traffic demand in metropolitan areas has far outpaced increases in freeway lane-miles in the United States. The solution to congestion lies in increasing the efficiency of existing infrastructure. Performance...

Evaluation of Portable Automated Data Collection Technologies: Interim Report, Work Accomplished During Fiscal Year 2005-2006

Banks, James H.
2006

This report documents work accomplished during Fiscal Year 2005-2006 as a part of a research project entitled “Evaluation of Portable Automated Data Collection Technologies.” Major activities during this period included a literature survey, surveys of potential users and vendors, preliminary evaluation of portable data collection technologies to select candidate systems for demonstration, and development of demonstration plans. There is demand for portable automated data collection systems for uses related to planning, traffic operations, traffic census, and traffic surveillance functions...

Transient Aerodynamic Effects on a Four-Car Platoon During Passing Maneuvers: Data Summary

Tsuei, L.
Hedrick, J. K.
Savas, O.
1999

In order to provide reliable control algorithms on PATH automated highway system, knowledge of the transient aerodynamic forces is important from the point of the controlla- bility of the platoon and individual vehicles. In a passing maneuver, the platoon members may experience severe aerodynamic forces and yaw moment when another vehicle overtakes. Similar phenomenon can be seen in our daily life as one car passes the other but much more complicated flow field is expected when the interaction involves in a multi-vehicle platoon. It is the purpose of this study to quantify the unsteady...

New Approach to Bottleneck Capacity Analysis: Final Report

Banks, James H.
2006

A capacity analysis approach intended as an alternative to the traditional Highway Capacity Manual (HCM) method was evaluated. One- and two-stage models of pre-queue and queue discharge flow (each of which might be thought of as representing “capacity” in some sense) were developed and compared with one another and the HCM method. Two-stage models related capacity flows to intervening variables, including average time gaps (average time separations between the rear of a vehicle and the front of one following it) in the critical lane (that with the highest flow rate) and the critical lane...

Safety Performance and Robustness of Heavy Vehicle AVCS

Yih, Paul
Satyan, Krishna
Gerdes, J. Christian
2003

Commercial heavy vehicle research at the California Partners for Advanced Transit and Highways (PATH) program has focused on the development of controllers for partially to fully automated driving environments. Safe performance of Advanced Vehicle Control Systems (AVCS) must be demonstrated for a wide range of operating conditions and truck configurations to avoid any one of the many failure modes-such as rollover or jackknifing-common to articulated heavy vehicles. For this purpose, a multi-body dynamic model of a tractor semitrailer has been developed using a commercially available...

Methods Of Analysis Of Ivhs Safety: Executive Summary

Hitchcock, Anthony
1992

This report presents the executive summary to a study on developing and demonstrating methods by which the safety of Intelligent Vehicle Highway Systems (IVHS) can be assured, assessed and evaluated. Safety considerations were studied for automated freeways, driver aids and copilots. Management and policy issues are briefly discussed in conclusion.

A Futures Market for Demand Responsive Travel Pricing

Fournier, Nicholas, PhD
Patire, Anthony, PhD
Skabardonis, Alexander, PhD
2023

Dynamic toll pricing based on demand can increase transportation revenue while also incentivizing travelers to avoid peak traffic periods. However, given the unpredictable nature of traffic, travelers lack the information necessary to accurately predict congestion, so dynamic pricing has minimal effect on demand. Dynamic toll pricing also poses equity concerns for those who lack other travel options. This research explores a potential remedy to these concerns by using a simple “futures market” pricing mechanism in which travelers can lock in a toll price for expected trips by prepaying for...

Layout, Design And Operation Of A Safe Automated Highway System

Hitchcock, Anthony
1995

This paper is concerned with the consequences of control system failures and external intrusions to a fully Automated Highway System (AHS). A model has been developed which enables the casualty rates in lines of automated vehicles to be calculated, following an initial event. It is applied to several situations here for a variety of possible physical layouts and operational modes of an AHS. It is believed that these configurations encompass all those proposed which are economically attractive, and that the accident types encompass the most important ones. For all accident types, there is...

Fault Detection And Identification With Application To Advanced Vehicle Control Systems: Final Report

Douglas, R. K.
Speyer, J. L.
Mingori, D. L.
Chen, R. H.
Malladi, D. P.
Chung, W. H.
1996

This study reports on a preliminary design of a health monitoring system for automated vehicles. A new detailed nonlinear vehicle simulation which extends the current simulation is documented and will be used as a future testbed for evaluating the performance of the health monitoring system. A health monitoring system has been constructed for the lateral and longitudinal modes that monitors twelve sensors and three actuators. The approach is to fuse data from dissimilar instruments using modeled dynamic relationships and fault detection and identification filters.