Roads/Highways

Freeway Analysis Manual: Parts 1 and 2

May, Dolf
Leiman, Lannon
2005

This Freeway Analysis Manual is intended for those who are responsible for understanding, analyzing, and evaluating the operations of freeways for planning, design, and operational improvements of such facilities. Freeway analysis requires a creative person, knowledgeable in freeway analysis fundamentals, having good traffic data, and selecting appropriate analytical tools.

Empirical Analysis of Traffic Breakdown Probability Distribution with Respect to Speed and Occupancy

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

From an operation viewpoint, traffic breakdown (from free-flow) was defined as when the average speed of traffic drops below a certain threshold. It is known that traffic breakdown is a stochastic phenomenon which can happen even when the traffic flow is below the capacity. The capacity has many definitions, such as that in HCM or the average of maximum daily flow. This study investigates the probability of breakdown at certain locations of freeway. The motivation is to find a practical capacity for each freeway section for active traffic control/operation purposes, which could be...

Extracting More Information from the Existing Freeway Traffic Monitoring Infrastructure

Coifman, Benjamin
2006

This report presents the results of TO 5302, Extracting More Information from the Existing Freeway Traffic Monitoring Infrastructure. This report represents significant advances in the PATH sponsored research into vehicle reidentification from conventional loop detectors, first by extending the methodology across major merge and diverge freeway sections. Second, it extends the methodology to single loop detectors. The report also extends the understanding of traffic phenomena impacting both traffic flow and the performance of the reidentification algorithms. It examines the impacts of lane...

Development and Performance Evaluation of AVCSS Deployment Sequences to Advance from Today's Driving Environment to Full Automation

Shladover, Steven
VanderWerf, Joel
Miller, Mark A.
Kourjanskaia, Natalia
Krishnan, Hariharan
2001

This report presents the findings of its investigation into deployment sequences to better understand the paths that could be taken from today's driving environment to vehicle-highway automation. One of the most vexing problems has always been that of determining how to advance from the present-day manually-controlled vehicles to the future fully automated vehicles. Considerable research attention has been devoted to defining the architecture and operating protocols, as well as the technology, of automated highway systems. Rather less attention has been devoted to defining the steps by...

A Machine Vision Based Surveillance System for California Roads

Malik, J.
Russell, S.
1995

In this report we address the problem of automation of heavy-duty vehicles. After a brief description of the dynamic model used in our design and simulations, we develop nonlinear controllers with adaptation, first for speed control and then for vehicle follower longitudinal control. We consider both autonomous operation as well as intervehicle communication, and evaluate the performance of our controllers in several different scenarios through simulation.

Spatial and Temporal Utility Modeling to Increase Transit Ridership

Church, Richard L.
Noronha, Val
Lei, Ting
Corrigan, Wils
Burbidge, Shaunna
Marston, Jim
2005

The objective of this research project was to develop a better understanding of the possible alternatives that a large employment center, like the University of California at Santa Barbara, can adopt in order to better utilize transit, mitigate traffic, and reduce demand for on-site parking. Although this project was oriented to the UCSB campus, the techniques and approaches developed in this project were designed to be equally applicable elsewhere. There were three major elements of this project: 1) develop an understanding of commuting employees through the use of a survey, 2) identify...

Distributed Surveillance and Control on Freeways

Coifman, Benjamin
2004

Efficient management of a road network requires continuous decision-making based on conditions on the network and an understanding of the impacts of the decisions made. These conditions are usually measured with fixed-point surveillance systems, most of which are deployed in such a manner as to require communication links that are always connected and are polled at regular intervals. All of the sensor data are typically sent to a Traffic Management Center (TMC) for assessment, yet most of the time no action is taken in response to the data, leading to unnecessarily high communication costs...

Implementation of a Tool for Measuring ITS Impacts on Freeway Safety Performance

Golob, Thomas F.
Marca, James
Recker, Will
2007

The research was undertaken to develop a tool for assessing the impacts of changes in freeway traffic flow on the level of traffic safety. Safety is measured in terms of the probability of a reportable accident, and the tool is so far restricted to urban freeway mainlines with substantial traffic levels. The tool will: (1) monitor the safety level of freeway operations (2) aid in freeway planning. The tool was calibrated by applying advanced statistical models to actual data combined from two sources: Vehicle Detector Station (VDS) data for freeways in Orange County (District 12), and data...

Integration of GPS/INS and Magnetic Markers for Advanced Vehicle Control Final Report for MOU 391

Farrell, Jay
Barth, Matthew
2002

This report describes the results of a project supported by California Partners for Advanced Transit and Highways (PATH). The main objective of the project is to develop and demonstrate a triple redundancy navigation system incorporating magnetometer, inertial, and carrier phase differential Global Positioning System (GPS) measurements. The motivating application for this project is lateral vehicle control. Therefore, the system was design to operate reliably whether or not GPS and magnetometer measurements were available. The navigation system provides vehicle position, velocity,...

PEDAMACS: Power Efficient and Delay Aware Medium Access Protocol for Sensor Networks

Coleri, Sinem
Varaiya, Pravin
2004

We consider a class of sensor networks with two special characteristics. First, the nodes periodically generate data for transfer to a distinguished node called the access point. Second, the nodes are (transmit) power and energy limited, but the access point, which communicates with the ‘outside world’, is not so limited. Such networks might be used for instance when a geographically distributed physical process, such as traffic on a freeway or at an urban street intersection, is periodically sensed for purposes of process control. We propose a medium access control scheme, called PEDAMACS...