PATH

Commuters' Normal and Shift Decisions in Unexpected Congestion: Pre-trip Response to Advanced Traveler Information Systems

Khattak, Asad
Polydoropoulou, Amalia
Ben-akiva, Moshe
1996

This report presents a study whose objective is to explore how people deal with unexpected congestion during the pre-trip stage and how they might respond to Advanced Traveler Information Systems (ATIS). Travelers' route, departure time and mode selection decisions were investigated through a survey of San Francisco Bay Area automobile commuters. The effects of various factors are examined, such as sources of congestion information, trip characteristics, and route attributes. The pre-trip response to future ATIS technologies is explored through stated preferences.

Commuter Response to Traffic Information on an Incident

Koo, Ronald
Yim, Youngbin
1998

This paper presents and discusses how traffic information is obtained and how it affects travel behavior when a major freeway is congested. Immediately following a major highway incident south of San Francisco which caused congestion, a telephone survey was conducted of commuters who utilize the affected corridor of highway. The behavior of commuters before and during their commute at the time of the incident was determined, including obtaining traffic information and how the information influenced changes in route, mode of travel and departure time. The results of the survey suggest that...

Communications and Positioning Systems in the Motor Carrier Industry

Scapinakis, Dimitris A.
Garrison, William L.
1991

Until recently, truck drivers and their dispatchers have relied on public telephones and voice radio systems to communicate with each other. Today, however, vendors are beginning to offer new technologies for determining the positions of trucks and communications to and from trucks. Eighteen systems and their implications for the industry and intelligent vehicle highway systems (IVHS) activities are reviewed in this paper. Some of the newer communications and/or positioning systems are in the proposal stage. Others are available with not yet fully developed capability or only in limited...

Coding of Road Information for Automated Highways

Guldner, J.
Patwardhan, S.
Tan, H.
Zhang, W.
1997

This paper discusses coding of road information in a lateral reference system using magnetic markers designed for Automated Highway Systems ( AHS). The coding is utilized to communicate road information such as up- coming road geometry or lane merges/diverges from the roadway infrastructure to AHS vehicles. The work presented here is based on experiences with the preparation of the I-15 test track near San Diego, CA, for the National AHS Consortium demonstration in 1997. Information about road features was encoded into the magnets used as a lateral reference system for automatic steering...

Collision Analysis of Vehicle Following Operations by Two-dimensional Simulation Model: Part I - Effects of Operational Variables

Chan, Ching-Yao
1997

This research project investigates the behaviors of vehicles in collisions, especially when they are closely spaced. The study uses a two- dimensional simulation program, EDSMAC, which allows longitudinal and lateral movements as well as the yaw motion of vehicles. The simulation model calculates impact forces in collisions and estimates the resulting vehicle damage. Collision situations are simulated. The subsequent post- impact vehicle trajectories are then analyzed. By varying parameters in simulation cases, one can evaluate the potential effects of such variables in vehicle-following...

Capacity of Automated Highway Systems: Effect of Platooning and Barriers

Tsao, H. S. Jacob
Hall, Randolf
Hongola, Bruce
1994

In this paper, the authors study the capacity of key Automated Highway Systems (AHS) operating scenarios. The effect of the lane-flow rule, platooning or free-agent, as well as the lane barriers, on AHS capacity are studied. Special attention is paid to the interaction between the lane-flow rule and the lane change requirement. The paper consists of two major components, analytical models and AHS simulation. After a brief introduction of AHS operating strategies, analytical models are developed for general AHS. For simulation, the authors focus on a segregated AHS that has one automated...

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

BTS (Version 1 .1) - Bottleneck Traffic Simulator User’s Manual

Lin, Wei Hua
Hall, Randolph W.
1991

BTS can be used to evaluate a variety of changes in highway design to improve bottlenecks, such as: (1) addition of highway lanes, (2) addition of automated or HOV lanes, or (3) incident management strategies to reduce the frequency, duration and magnitude of incidents. BTS can also be used to project future highway conditions as baselevel traffic grows or driver behavior changes.The new version of BTS was enhanced to include incident dependencies, variable weather conditions, reneging, and randomly varying traffic volumes. As of yet, BTS is not capable of analyzing highway performance on...

Brake System Modeling, Control and Integrated Brake/Throttle Switching Phase I

Hedrick, Karl
Gerdes, J.C.
Maciuca, D.B.
Swaroop, D.
1997

This report is concerned with the modeling and control issues regarding braking in an Intelligent Transportation Systems (ITS) setting. Specifically, it addresses the issue of vehicle control in an automated highway system, brake actuation and coordinated brake and throttle switching. It first presents a hydraulic model of the brake system. A method for designing stable controllers for uncertain, mismatched nonlinear system is then described. A method to estimate the coefficient between the brake pressure at the wheel and the brake torque is presented. The next section describes a...

Brake Dynamics Effect On IVHS Lane Capacity

Maciua, Dragos B.
1994

This paper attempts to assess the effects of brake system dynamics and inter-vehicle communication delays (microscopic characteristics) on the capacity of an automated highway system (macroscopic characteristics). Simulations were conducted to investigate the relationship between the microscopic and macroscopic characteristics. Recommendations are made regarding the maximum desired delays, intra-platoon and inter-platoon distances and platoon size in order to achieve the highest possible capacity while maintaining a high degree of safety.