Traffic Operations and Management

Model Selection and Initial Application of CONTRAM Model for Evaluating In-Vehicle Information Systems

Gardes, Yonnel
Haldors, Bruce
May, Adolf D.
1991

The objectives of this study were to select a traffic assignment and simulation model, apply that model to an integrated freeway/arterial network such as the Smart Corridor in Los Angeles, California, and, using the model, make an initial evaluation of in-vehicle information systems and the applicability of the model.

Methodologies for Assessing the Impacts of Highway Capacity Enhancements on Travel Behavior

Liu, Heng
Hall, Randolph
1998

Acceptance of ITS components that are designed to increase capacity will hinge on the extent to which additional capacity induces additional travel. This study addressed methodologies for studying the effects of capacity on travel: 1) before and after studies or travel times and volumes in corridors in which capacity had been increased, 2) surveys of users of routes on which capacity had been increased, and 3) statistical changes in county VMT as a function of freeway capacity. On I-80 in the Bay Area, the site selected for the investigation, travel times and volumes were quite variable....

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.

Longitudinal Control of a Platoon of Vehicles. II, First and Second Order Time Derivatives of Distance Deviations

Sheikholeslam, Shahab
Desoer, Charles A.
1989

This report is an addendum to PATH Research ReportUCB-ITS-PRR-89-3.

Lateral Control of Commuter Buses

Hingwe, Pushkar
Tomizuka, Masayoshi
1995

This report presents two approaches to the design of the lateral controllers for commuter buses based on Sliding Mode Control (SMC). The objective of the control is to track the lane centerline. The first controller uses the sensor output which is a combination of yaw and lateral error. The second controller achieves tracking objective by providing a yaw rate to the vehicle so as to keep the lateral error dynamics stable. The two controllers are compared by performing simulations for a range of parameters.

Intelligent Sensor Validation and Fusion for Vehicle Guidance Using Probabilistic and Fuzzy Methods

Agogino, Alice
Goebel, Kai
Alag, Sanam
1997

This study reports on a method to accomplish sensor validation and fusion in Intelligent Transportation Systems (ITS). The method is based on probabilistic and fuzzy techniques that express a confidence in the sensor data and take into account environmental factors and the state of the system. Sensor data fusion uses the confidence assigned to each sensor reading and integrates them into one reading. Noise and failure are filtered from the data and lead to a safety improvement in ITS.

Intelligent Cruise Control Systems and Traffic Flow Stability

Darbha, Swaroop
Rajagopal, K.r.
1998

In analogy to the flow of fluids, it is expected that the aggregate density and the velocity of vehicles in a section of a freeway adequately describe the traffic flow dynamics. The conservation of mass equation together with the aggregation of the vehicle following dynamics of controlled vehicles describes the evolution of the traffic density and the aggregate speed of a traffic flow. There are two kinds of stability associated with traffic flow problems - string stability (or car-following stability) and traffic flow stability. We make a clear distinction between traffic flow stability...

Implementing a Dynamic O-D Estimation Algorithm within the Microscopic Traffic Simulator Paramics

Garcia, Reinaldo C.
2002

California has long recognized the potential for applying electronic and other transportation systems technologies to address the significant mobility and economic challenges in the state,and the rest of the nation.Through an aggressive Advanced Transportation Systems Program,Intelligent Transportation Systems (ITS)are being researched,built,and tested for deployment.These ITS will address today s transportation needs and those of the twenty-first century.An important element of this program is the California Advanced Transportation Management Systems Testbed (California ATMS Testbed)...

Fuzzy Logic Traction Controllers and Their Effect on Longitudinal Vehicle Platoon Systems

Bauer, M.
Tomizuka, M.
1995

This paper presents fuzzy logic traction controllers and their effect on longitudinal vehicle platoon systems. A fuzzy logic approach is appealing for traction control because of the non-linearities and time-varying uncertainties in traction control systems. One fuzzy controller estimates the "peak slip" corresponding to the maximum tire-road adhesion coefficient and regulates wheel slip at that value. The other fuzzy logic controller regulates wheel slip at any desired value. The controllers' performance and robustness against changing road conditions and time- varying uncertainty is...

Freeway Traffic Oscillations: Observations and Predictions

Mauch, Michael
Cassidy, Michael J.
Taylor, Michael A. P.
2002

Freeway traffic was observed over multiple days and was found to display certain regular features. Oscillations arose only in queues; they had periods of several minutes; and their amplitudes stabilized as they propagated upstream. They propagated at a nearly constant speed of about 22 to 24 kilometers per hour, independent of the location within the queues and the flow measured there; this was observed for a number of locations and for queued flows ranging from about 2,000 to 850 vehicles per hour per lane. The effects of the oscillations were not felt downstream of the bottleneck. Thus,...