Roads/Highways

Tools for Operations Planning (TOPL2)

Varaiya, Pravin
2009

TOPL is a suite of tools to specify operational improvements including ramp metering, incident and demand management, auxiliary lanes, traveler information, and to quickly estimate the benefits that such improvements can realize. TOPL is based on the macroscopic cell transmission model (CTM). Advances under TOPL2 can be classified under (1) theory, (2) software and algorithms, and (3) applications.In terms of theory, the CTM model for a freeway was thoroughly analyzed and extended to arterials. In software, the major advance was the development of Aurora—an object-oriented simulation...

Safe Platooning In Automated Highway Systems

Alvarez, Luis
Horowitz, Roberto
1997

This report addresses the problem of designing safe controllers for the hybrid system composed by the interaction of the regulation and coordination layers in the hierarchical California PATH Automated Highway System (AHS) architecture. Conditions to achieve safe platooning under normal mode of operation are investigated. The results that are obtained allow for the decoupling of the design and verification of the regulation and coordination layers in the PATH AHS architecture.

Command Modification Using Input Shaping for Automated Highway Systems with Heavy Trucks

Bae, Hong S.
Gerdes, J. Christian
2004

Automated vehicles require sufficiently accurate system models in order to achieve a desired level of closed-loop performance in, for example, automated highways systems or smart cruise control systems. Parameters of the models are one of the important factors that determine the accuracy of system modeling and, eventually, the overall performance of the closed-loop system. Current GPS sensing technology enables estimation of road grade and, consequently, simple treatment of parameter estimation from a static force balance. This work has demonstrated that road grade can be reliably...

Freeway Safety as a Function of Traffic Flow: The FITS Tool for Evaluating ATMS Operations

Golob, Thomas F.
Recker, Wilfred W.
Alvarez, Veronica
2002

Understanding the benefits of improved traffic flow (reduced congestion) is critical to the assessment of investments in infrastructure or traffic management and control. Improved flow should lead to reductions in travel time, vehicle emissions, fuel usage, psychological stress on drivers, and improved safety. However, the manner in which safety is improved by smoothing traffic flow is not well understood. The documented research is aimed at shedding light on the complex relationships between traffic flow and traffic accidents (crashes).

Vehicle To Roadside Communications Study

Polydoros, Andreas
Dessouky, Khaled
Pereira, Jorge M. N.
Sun, Chung-ming
Lee, Kuo-chun
Papavassiliou, Thomas D.
Li, Victor O. K.
1993

The objective of this study is to address the communication system design issues of Intelligent Vehicle Highway Systems (IVHS). The focus of Phase I of this research is the design for California Advanced Driver Information Systems (CADIS). The emphasis is on the architecture and topology aspects of the physical link and access layers connecting the moving layers with the fixed infrastructure. The work is divided into the following categories: Automatic Vehicle Identification (AVI), IVHS communications survey and functional requirements, modeling of IVHS fading channels, multiple-access...

Determining the Effectiveness of HOV Lanes

May, Adolf D.
Leiman, Lannon
Billheimer, John
2007

This document is the final report for the two-year PATH Project “Determining the Effectiveness of HOV Lanes”. It has been supported by the California Department of Transportation (Caltrans). The primary objectives of this project have been to evaluate freeways having on-freeway HOV lanes in terms of vehicle-travel, person-travel, occupancy distribution, shape and duration of the peak period, congestion patterns, and air quality both in the HOV lane and the adjacent mixed-flow lanes.Based on a comprehensive literature review an extensive list of reference was developed, along with summaries...

Sensor-Friendly Freeways: Investigation of Progressive Roadway Changes to Facilitate Deployment of AHS

Misener, James A.
Griffiths, Paul
Johnson, Lee
Segal, Andy
2001

Intelligent "driver assistance" systems which utilize in-vehicle forward-looking sensors can be supplemented by vehicle-vehicle and vehicle-highway cooperative elements to comprise a "sensor-friendly" highway environment that would enhance the operational efficiency, and ultimately, the safety benefits of these systems. In our research, we have identified the current limitations of autonomous sensing systems in target/background discrimination with cluttered highways. Based upon this, and by limiting ourselves to "sensed" (and not wireless) systems, we have conceived relatively inexpensive...

Real-time Density Estimation on Freeway with Loop Detector and Probe Data

Qiu, Tony Z.
Lu, Xiao-Yun
Chow, Andy H. F.
Shladover, Steven
2009

Density, speed and flow are the three critical parameters for traffic analysis. Traffic management and control with high performance require accurate estimation/prediction of distance mean speed and density for large spatial and temporal coverage. Speed, including time mean speed and distance mean speed, and flow estimation are relatively easy to be measured and estimated in the practical site, but accurate density estimation is very difficult. Inductive loop detector systems have been widely deployed, it makes better sense to fully adopt available infrastructure to achieve required...

Models, Simulation, And Performance Of Fully Automated Highways

Varaiya, Pravin
1994

The research findings presented in this report deal with the modeling, simulation and performance evaluation of fully automated highway systems ( AHS). The report begins with a brief reconstruction of the history of the AHS concept, and a particular AHS proposal that has been intensely studied in PATH. The next section summarizes the principal findings of AHS performance. This is followed by an overview of the simulation program SmartPath. An outline of the current work on SmartPath and plans for the immediate future are given. This section also proposes an object oriented distributed...

Implementation and Evaluation of Automated Vehicle Occupancy Verification

Chan, Ching-Yao
Bu, Fanping
Singa, Krute
Wang, Huili
2011

Vehicle occupancy verification is a principal impediment to more efficient HOV/HOT lane enforcement. However, no automated solution has yet been developed for permanent field implementation. Given widespread plans for development of HOV and HOT lanes in a number of metropolitan areas, improved vehicle occupancy verification techniques urgently need to be explored as well as the legal and institutional barriers to their implementation.A research project to evaluate the technologies for vehicle occupancy verification was conducted by California PATH of University of California at Berkeley....