Traffic Operations and Management

Experimental Characterization of Multi-Lane Freeway Traffic Upstream of an Off-Ramp Bottleneck

Munoz, Juan Carlos
Daganzo, Carlos
2000

This report describes field observations of multi-lane freeway traffic upstream of an oversaturated off-ramp. It is based on empirical evidence from freeway I-880 (northbound) near Oakland, California. The report presents two diagnostic tools that reveal hidden features of the traffic stream and, based on these findings, proposes congestion mitigation strategies that could work for similar locations with little or no construction.

Major Failure Events of Automated Highway Systems: Three Scenarios from the Driver’s Perspective

Tsao, H.-S. Jacob
Plocher, Thomas A.
Zhang, Wei-Bin
Shladover, Steven E.
1997

Automated Highway Systems (AHS) have the potential for offering large capacity and safety gains without requiring significant amounts of additional right-of-way. Since the general public will be the users of the AHS, human factors must play a pivotal role in the research and development of AVCS technologies and AHS operation. In two companion reports, three attributes critical to AHS human factors were identified and seven scenarios featuring variations in these attributes proposed. To ensure the identification of all major compounding attribute combinations, detailed operational events,...

Time Space Diagrams For Thirteen Shock Waves

Coifman, Benjamin
1997

This paper presents microscopic time-space diagrams for several shock waves over 100-200m distances. The primary focus of the paper is on presenting the data rather than analysis. The diagrams should be of general interest to researchers studying traffic congestion.

A Link-Based Variational Inequality Model for Dynamic Departure Time/Route Choice

Ran, Bin
Hall, Randolph
Boyce, David E.
1995

The dynamic user-optimal (DUO) departure time and route choice problem is to determine travelers’ best departure times and route choices at each instant of time. In a previous paper, we presented a route-based two-level optimal control model for the DUO departure time/route choice problem. However, this model is not appropriate for large scale transportation networks because some degree of route enumeration is necessary to solve the model. In this paper, we present a link-based variational inequality (VI) formulation for the DUO departure time/route choice problem so that route enumeration...

Robust Computation of Optical Flow in a Multi-Scale Differential Framework

Weber, Joseph
Malik, Jitendra
1993

We have developed a new algorithm for computing optical flow in a differential framework. The image sequence is first convolved with a set of linear, separable spatiotemporal filters similar to those that have been used in other early vision problems such as texture and stereopsis. Our analysis of the measurement errors leads us to develop an algorithm based on a robust version of total least squares. Each optical flow vector computed has an associated reliability measure which can be used in subsequent processing. The performance of the algorithm on the data set used by Barron et al. (...

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...