Traffic Operations and Management

Los Angeles Fot Spread Spectrum Radio Traffic Signal Interconnect Evaluation Task: Final Report On Full Deployment

Li, Victor O. K.
Sengodan, Senthil
Chan, Tat-keung Ken
Zhuge, Lei
1998

This report presents the results of an evaluation of project in which spread spectrum radio networks (SSRN) were used for traffic monitoring and control in the City of Los Angeles. The focus of SSRN is to reduce construction costs, construction time and future plant maintenance costs. A field operational test was conducted to test and evaluate the applicability of SSRN communications in traffic control.

A Method for Relating Type of Crash to Traffic Flow Characteristics on Urban Freeways

Golob, Thomas F.
Recker, Wilfred W.
2003

A method is developed to determine how crash characteristics are related to traffic flow conditions at the time of occurrence. Crashes are described in terms of the type and location of the collision, the number of vehicles involved, movements of these vehicles prior to collision, and severity. Traffic flow is characterized by central tendencies and variations of traffic flow and flow/occupancy for three different lanes at the time and place of the crash. The method involves nonlinear canonical correlation applied together with cluster analyses to identify traffic flow regimes with...

TMDD Standards Review Technical Memorandum

Peterson, Brian
2021

This document presents a review of the Traffic Management Data Dictionary (TMDD) standard, specifically version 3.03d with some analysis of the newest version 3.1, released in January 2020. The intention of this document is to provide a review of this standard for transmission of data between traffic management centers (TMCs), with specific commentary on usability of the standard with specific examples based on its implementation in the Caltrans I-210 Connected Corridors program. TMDD is published by the Institute of Transportation Engineers (ITE), an international organization of...

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...

Trav Info Evaluation: The Target Study Phase 1 Results

Koo, Ronald
Yim, Younbin
Hall, Randolph
1998

This paper discusses how traffic information is obtained and how the congestion of a major freeway affects travel behavior. Immediately following two congestion-causing major highway incidents south of San Francisco, telephone surveys were conducted of commuters who utilize the affected corridor of highway. The incidents took place two weeks apart on the same corridor of US-101, the first affecting southbound traffic and the second affecting northbound traffic. The travel behavior of commuters before and during their commute at the time of each incident was determined, including how they...

PATH ITS Research Digests

Chira-Chavala, Ted
2001

Ramp meters are commonly used to relieve congestion on freeways. What is the value of these systems? Ramp metering can alleviate recurrent, regular traffic congestion, such as that caused by the daily commute. The goal is usually to maintain uninterrupted freeway flow at a certain acceptable level, but it transfers delay to the entrance ramp, where excess demand is forced to wait. This report summarizes ramp metering technologies, reviews the algorithms commonly used with them, and uses a traffic simulation model to identify the benefits and costs of using these systems. We used a...

Database Environment for Fast Real-Time Simulation of Urban Traffic Networks with ATMIS

Jayakrishnan, R.
Sheu, Phillip
Wang, Taehyung
Xu, MinHua
2000

This project develops the environment for using the ATMIS simulation software developed under previous PATH projects (MOUs 39, 84, and 170) for real-time traffic simulation and scenario analysis with feedback from the real urban network. keywords: traffic simulation, databases, object-relation databases, dynasmart

Evaluation of Potential ITS Strategies Under Non-Recurrent Congestion Using Microscopic Simulation

Chu, Lianyu
Liu, Henry X.
Recker, Will
Hague, Steve
2003

This report presents a micro-simulation method to evaluate potential ITS applications. Based on the commercial PARAMICS model, a capability-enhanced PARAMICS simulation environment has been developed through integrating a number of plug- in modules implemented with Application Programming Interfaces (API). This enhanced PARAMICS simulation can thus have capabilities to model not only the target traffic conditions and operations but also various potential ITS strategies. An evaluation study on the effectiveness of potential ITS strategies under the incident scenarios is conducted over a...

"Study of Traffic at a Freeway Merge and Roles for Ramp Metering"

Cassidy, Michael J.
Rudjanakanoknad, Jittichai
2002

Traffic data measured near the junction of a single-lane on-ramp (with metered inflows) and a three-lane freeway were carefully studied for four days during the rush. The data showed the area around this merge junction became a bottleneck each day when the on-ramp's meter allowed its inflows to rise in the presence of high flows arriving from the freeway. Detailed study during these times further showed that queueing actually arose some distance downstream of the merge and that these queues were caused by drivers who, having just entered the freeway's shoulder lane from the on-ramp, slowed...

Median Light Rail Crossing: Accident Causation And Countermeasures

Coifman, Benjamin
Bertini, Robert L.
1997

This paper focuses on accident causation and countermeasures at arterial median light rail grade crossings. It synthesizes accident causation and prevention literature from several fields, including traffic engineering, human factors and cognitive psychology, as it relates to the complex LRT grade crossing.