Roads/Highways

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].

Modeling IVHSEmission Impacts. Volume 1: Background Issues And Modeling Capabilities

Guensler, Randall
Washington, Simon
Sperling, Daniel
1994

This paper examines the potential air quality impacts of Intelligent Vehicle Highway Systems (IVHS) upon important emission-producing vehicle activities and those parameters that affect emission rates. Important emission relationships are identified, a framework for comparative analysis is developed, and the general relationships between IVHS technology bundle characteristics and vehicle emission impacts are examined. The primary IVHS emission-related impacts that this project addresses are associated with changes in the average speed and operating mode (acceleration, deceleration, cruise...

The Los Angeles Freeway Service Patrol (fsp) Evaluation: Study Methodology And Preliminary Findings

1997

This paper presents a methodology to evaluate a benefit-to-cost ratio effectiveness of the Freeway Service Patrol in a freeway section in Los Angeles. The methodology addresses the process of estimating incident delay using probe vehicles and the lack of "before" data.

Structure of the Transition Zone Behind Freeway Queues

Munoz, Juan Carlos
Daganzo, Carlos
2000

Observations of freeway traffic flow are usually quite scattered about an underlying curve when plotted versus density or occupancy. Although increasing the sampling intervals can reduce the scatter, whenever an experiment encompasses a rush hour with transitions in and out of congestion, some outlying data stubbornly remain beneath the "equilibrium" curve. The existence of these non-equilibrium points is an ill-understood phenomenon that appears to contradict the simple kinematic wave (KW) model of traffic flow. This paper provides a tentative explanation of the phenomenon, based on...

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...

BTS (version 1.0): Bottleneck Traffic Simulator User's Manual

Lin, Wei Hua
Hall, Ranolph W.
1991

Describes the computer program BTS which is a macroscopic tool for simulating the performance of freeway bottlenecks