Roads/Highways

Dynamic Modeling Of Tractor-semitrailer Vehicles In Automated Highway Systems

Chen, Chieh
Tomizuka, Masayoshi
1995

This report is concerned with the dynamic modeling of the tractor- semitrailer vehicles in Automated Highway Systems (AHS). The objectives of the research are to characterize the dynamic response of articulated heavy-duty vehicles, identify the key system parameters, develop control algorithms to achieve automatic guidance, and conduct experiments on lateral guidance control of articulated heavy-duty vehicles. A modeling approach for roll, pitch and yaw motions of tractor-semitrailer vehicles is described.

Trav Info Evaluation ( Technology Element ) Traveler Information Center ( TIC ) Study: Operator Interface Analysis - Phase III

Miller, Mark
Loukakos, Dimitri
1998

TravInfo is a Field Operational Test of advanced traveler information systems for the San Francisco Bay Area, sponsored by the Federal Highway Administration (FHWA). The project involves a public/private partnership which seeks to compile, integrate and broadly disseminate timely and accurate multi-modal traveler information through commercial products and services. The public sector component centers on the Traveler Information Center (TIC), which collects and integrates both static and dynamic traveler information. The TIC began operations in September 1996 and will operate as an FOT...

Incident Management: Process Analysis And Improvement Phase 1: Review Of Procedures

Hall, Randolph
Mehta, Yatrik
1998

This working paper examines the process for managing incidents on highways, as it is applied in Los Angeles County. The examination is based on interviews with various agencies, including law enforcement, state highway department, coroners office, and LA County MTA Freeway Service Patrol, along with direct observation through ride-alongs. Follow-up work will quantify the benefits of improved incident management, through analysis of freeway performance and response characteristics during incidents.

New Aggregation Strategies to Improve Velocity Estimation from Single Loop Detectors

Coifman, Benjamin
Lee, Zu-Hsu
2000

Loop detectors are the preeminent vehicle detector for freeway traffic surveillance. Although single loops have been used for decades, debate continues on how to interpret the measurements. Many researchers have sought better estimates of velocity from single loops. The preceding work has emphasized post-processing techniques. Although rarely noted, these techniques effectively seek to reduce the bias due to long vehicles in measured occupancy and flow. This paper presents a different approach, using a new aggregation methodology to estimate velocity and reduce the impact of long vehicles...

AHS Deployment: A Preliminary Assessment of Uncertainties

Hall, Randolph W.
Tsao, H.-S. Jacob
1994

This paper provides a preliminary assessment of uncertainties, both technical and institutional, associated with the deployment of Automated Highway Systems (AHS). Seven issues are addressed, concerning whether: (1) People use AHS, ( 2 ) Auto makers manufacture equipped vehicles, (3) Government builds AHS roadways, (4)Highways can evolve, ( 5 ) Interest groups do not obstruct, (6) Performance is adequate, and (7) Technology is feasible. For each issue, a table is provided that lists some of the more critical uncertainties.

Towards a Technology Assessment of Highway Navigation and Route Guidance

Kanafani, Adib
1987

This paper is intended as a first look at the required assessment of technology. It is preliminary in the sense that it attempts to identify the issues and to identify some aspects of technology assessment that are needed to deal with them. It's aim is to raise some of the fundamental questions that arise in connection with the evaluation of this technology, and to suggest some further work for dealing with them. A more extensive research plan for looking at the various aspects of automobile navigation is to be found in Gosling [1988].

Incident Dispatching, Clearance and Delay

Hall, Randolph
2000

This report models response times and delays for highway incidents, according for spacing between interchanges and the time penalty for changing directions, enabling a response vehicle to reach an incident on the opposite side of the highway. A fundamental question in dispatching incident crews is whether to send the closest vehicle that is currently available or to wait for another to become available that is even closer. Waiting for a closer one is advantageous because service time is effectively reduced, adding to capacity and providing stability at higher levels of utilization. But...

California Transportation Management Centers Part 1. Assessment Of Existing Capabilities

Lo, Hong K.
Hall, Randolph W.
Windover, John R.
1993

Transportation Management Centers (TMCs) are focal points for monitoring and operating traffic management systems. As new technologies are developed through research in Intelligent-Vehicle- Highway Systems (IVHS), these TMCs will assume increasingly more importance as command and control centers for transportation operations. This study is aimed at developing visions for how the TMC of the future will exploit the capabilities of IVHS. Part 1 of this study, reported herein, is an assessment of existing TMC capabilities in the State of California. Part 2, to be reported later, will develop...

Relationships Among Urban Freeway Accidents, Traffic Flow, Weather and Lighting Conditions

Golob, Thomas F.
Recker, Wilfred W.
2001

Linear and nonlinear multivariate statistical analyses are applied to determine how the types of accidents that occur on heavily used freeways in Southern California are related to both the flow of traffic and weather and ambient lighting conditions. Traffic flow is measured in terms of time series of 30-second observations from inductive loop detectors in the vicinity of the accident prior to the time of its occurrence. Results indicate that the type of collision is strongly related to median traffic speed and to temporal variations in speed in the left and interior lanes. Hit-object...

Freeway Performance Measurement System: Final Report

Varaiya, Pravin
2001

PeMS is a freeway performance measurement system for all of California. It processes 2GB/day of 30-second loop detector data in real time to produce useful information. Managers at any time can have a uniform and comprehensive assessment of freeway performance. Traffic engineers can base their operational decisions on knowledge of the current state of the freeway network. Planners can determine whether congestion bottlenecks can be alleviated by improving operations or by minor capital improvements. Travelers can obtain the current shortest route and travel time estimates. Researchers can...