Data

Empirical Comparison of Travel Time Estimation Methods

Zhang, Xiaoyan
Rice, John
Bickel, Peter
1999

In this paper, we conduct an empirical comparison of travel time estimation methods based on single-loop detector data. The methods of concern are the regression method based on an intuitive stochastic model as proposed by Petty et al. in [7], and the conventional method of using an identity relating speed, flow and occupancy with the assumption of a common vehicle length. The analysis is tailored to fit in the limitations imposed by available field data sets. We also introduce several variations of the regression method and give examples which suggest directions for future work to further...

Address Resolution in One Lane Automated Highway Systems

Bana, Soheila V.
Varaiya, Pravin
1999

Address Resolution Protocols (ARP) are used in Automated Highway Systems (AHS) to establish communication among vehicles. The purpose of the ARP is to determine the network address of neighboring vehicles. We are proposing an innovative solution that takes advantage of the automated road infrastructure. For providing addresses initially and uses the communication network itself for updating the network communication addresses in a one lane automated highway system. The protocol has been modeled using PROMELA [1], and simulated and verified by SPIN [2]. SPIN is a tool for analyzing the...

Aerodynamic Forces on Truck Models, Including Two Trucks in Tandem

Hammache, Mustapha
Michaelian, Mark
Browand, Fred
2001

The present wind tunnel experiment describes 6-component force and moment data measured for both the cab and the trailer of a simplified model truck. Forces and moments are presented in coefficient form. The cab is sufficiently smooth that no flow separation occurs at zero yaw. The trailer has rounded forward vertical edges and sharp upper and lower edges. Both cab and trailer have wheels. The test matrix includes variation of the cab-trailer gap, and the yaw angle between the model plane of symmetry and the axis of the wind tunnel. The yaw angle is meant to account for the presence of an...

Freeway Performance Measurement System (PeMS)

Chen, Chao
2003

The freeway Performance Measurement System (PeMS) collects real time traffic data from sensors and generates performance measures of vehicle miles traveled, hours traveled, and travel time. This project is sponsored by the California Department of Transportation (Caltrans). PeMS provides tools and reports for traffic planners, operators, and engineers. It has a Web interface. Growing traffic demand in metropolitan areas has far outpaced increases in freeway lane-miles in the United States. The solution to congestion lies in increasing the efficiency of existing infrastructure. Performance...

Evaluation of Portable Automated Data Collection Technologies: Interim Report, Work Accomplished During Fiscal Year 2005-2006

Banks, James H.
2006

This report documents work accomplished during Fiscal Year 2005-2006 as a part of a research project entitled “Evaluation of Portable Automated Data Collection Technologies.” Major activities during this period included a literature survey, surveys of potential users and vendors, preliminary evaluation of portable data collection technologies to select candidate systems for demonstration, and development of demonstration plans. There is demand for portable automated data collection systems for uses related to planning, traffic operations, traffic census, and traffic surveillance functions...

Transient Aerodynamic Effects on a Four-Car Platoon During Passing Maneuvers: Data Summary

Tsuei, L.
Hedrick, J. K.
Savas, O.
1999

In order to provide reliable control algorithms on PATH automated highway system, knowledge of the transient aerodynamic forces is important from the point of the controlla- bility of the platoon and individual vehicles. In a passing maneuver, the platoon members may experience severe aerodynamic forces and yaw moment when another vehicle overtakes. Similar phenomenon can be seen in our daily life as one car passes the other but much more complicated flow field is expected when the interaction involves in a multi-vehicle platoon. It is the purpose of this study to quantify the unsteady...

Fault Detection And Identification With Application To Advanced Vehicle Control Systems: Final Report

Douglas, R. K.
Speyer, J. L.
Mingori, D. L.
Chen, R. H.
Malladi, D. P.
Chung, W. H.
1996

This study reports on a preliminary design of a health monitoring system for automated vehicles. A new detailed nonlinear vehicle simulation which extends the current simulation is documented and will be used as a future testbed for evaluating the performance of the health monitoring system. A health monitoring system has been constructed for the lateral and longitudinal modes that monitors twelve sensors and three actuators. The approach is to fuse data from dissimilar instruments using modeled dynamic relationships and fault detection and identification filters.

Evaluating the Costs and Benefits of Transit Smart Cards

Iseki, Hiroyuki, PhD
Demisch, Alexander
Taylor, Brian D., PhD
Yoh, Allison C., MA
2008

Smart cards are gaining momentum as transit agencies across the country have been implementing them as a fare medium. Smart cards hold the promise of revolutionizing the way riders use transit, and how transit systems operate. But in order to adopt smart cards, transit agencies must purchase new equipment and upgrade their entire fare collection system – a very expensive process. In addition, many of the oft-touted benefits of smart cards are vague, and it is not at all certain if they are worth the high cost of implementation.This study examines how transportation agencies in three...

Adaptive Baud Protocol For Wireless Communication

Eskafi, F. H.
Nassiri-toussi, K.
Liu, G.
1998

In this paper, the authors propose an algorithm that increases and decreases the transmission speed according to a user-specified function. The design objective is to regulate baud as efficiently as possible and ensure that in each transmission interval, transmitter and receiver bauds are equal for some period of time during data transmission. An equivalent discrete-time version of the protocol is verified by using the COSPAN software. Application for this adaptive baud protocol for wireless communication is seen in a platoon setting within an Automated Highway System (AHS).

GPS/GIS Technologies for Traffic Surveillance and Management: A Testbed Implementation Study

McNally, M.G.
Marca, J.E.
Rindt, C.R.
Koos, A.M.
2002

The fundamental principle of intelligent transportation systems is to match the complexity of travel demands with advanced supply-side analysis, evaluation, management, and control strategies. A fundamental limitation is the lack of basic knowledge of travel demands at the network level. Modeling and sensor technology is primarily limited to aggregate parameters or micro-simulations based on aggregate distributions of behavior. Global Positioning Systems (GPS) are one of several available technologies which allow individual vehicle trajectories to be recorded and analyzed. Potential...