PATH

Vehicle Reidentification and Travel Measurements on Congested Freeways

Coifman, Benjamin
1999

This paper presents a vehicle reidentification algorithm for consecutive detector stations on a freeway, whereby a vehicle measurement made at a downstream detector station is matched with the vehicle's corresponding measurement at an upstream station. The method is illustrated using measured vehicle lengths from paired loop detector speed traps. Where speed traps are quite common, often placed at half mile spacings or less on urban freeways. In conventional operation, these detectors only monitor traffic conditions over the loops, leaving most of the freeway unmonitored. By taking the...

Collecting Road Traffic Data Using ALOHA Mobile Radio Channel

Linnartz, Jean-Paul M.G.
Gamba, David P.
1993

This report proposes a spectrum efficientsolution for transmitting link travel times from vehicles to a central infrastructure. The performance of an ALOHA mobile radio system for this application is studied analytically. The average number of new updates per minute and the expected time lapsed since the latest update of the road traffic situation in a particular street section is obtained. Results show that in an urban environment, a single (cellular) radio channel has sufficient capacity if receivers are located every 5 to 10 km.

Multi-Sensor Traffic Data Fusion

Kim, ZuWhan
Skabardonis, A.
2003

This report describes unique surveillance system on a section of I-80 freeway in the city of Emeryville. The system, called the Berkeley Highway Laboratory (BHL), consists of eight dual loop detector stations along the freeway section, and 12 video cameras. Advanced machine vision algorithms were developed to process the video data to generate vehicle trajectories. Efforts are underway to fuse the loop and video detector data to obtain detailed and accurate information on traffic operating conditions

Inter Vehicle Spacing: User's Manual (2 Diskettes Included)

Ioannou, P.
Kanaris, A.
Grammagnat, A.
1997

This documentation and software provides a tool which enable a user to perform the following tasks regarding vehicle spacing:; calculate the minimum initial spacing between two vehicles, calculate the possibility and severity of collision between two vehicles, visualize the motion of the two vehicles in the longitudinal direction during braking maneuvers, and calculate the highway capacity given factors for velocity, spacing, and size of vehicles and platoons.

TravInfo Field Operational Test Institutional Evaluation Final Results

Yim, Youngbin
Deakin, Elizabeth
2000

This paper documents the final analysis of a three part series of institutional evaluations of the TravInfo Field Operational Test from its inception in 1992 through its completion in 1998. The Field Operational Test was performed over a two-year period from September 1996 to September 1998. Funding for the TravInfo evaluation was from the Federal Highway Administration with a matching grant from the California Department of Transportation (Caltrans). The institutional evaluation examined TravInfo's unique concept of open-architecture and its collaborative public-private partnership to...

Robust Automatic Steering Control for Look-Down Reference Systems with Front and Rear Sensors

Guldner, Jurgen
Sienel, Wolfgang
Tan, Han-Shue
Ackerman, Jurgen
Patwardhan, Satyajit
Bunte, Tilman
1997

This paper describes a robust control design for automatic steering of passenger cars. Previous studies [l-3] showed that' reliable automatic driving at highway speed may not be achieved under practical conditions with look-down reference systems which use only one sensor at the front bumper to measure the lateral displacement of the vehicle from the lane reference. An additional lateral displacement. sensor is added here at the tail bumper to solve the automatic steering control problem. The control design is performed stepwise: First, an initial controller is determined using the...

Investigation Of An Optical Method To Determine The Presence Of Ice On Road Surfaces

Misener, James
1998

This report presents a review of alternative techniques to determine the presence of ice on road surfaces. It examines techniques ranging from passive, in-pavement technologies, to different remote sensing techniques. The author presents the Polarized Reflectance Infrared Signature Method (PRISM) technique which uses differences in measured near infrared reflectance between ice, water and dry road due to absorption, in addition to the effect of polarization to discount the contribution of specutacular reflectance off the front surface.

Field Deployment and Operational Test of an Agent-based, Multi-Jurisdictional Traffic Management System

Rindt, Craig R.
McNally, Michael G.
2007

This report describes a reinterpretation of how the philosophy underlying the Cartesiusmulti-jurisdictional incident management prototype can be used as an organizing princi-ple for real-world multi-jurisdictional systems. This interpretation focuses on the power ofthe Distributed Problem Solving (DPS) approach Cartesius uses to partition analysis andoptimization functions in the system across jurisdictions. This partitioning minimizes theamount of local information that must be shared between jurisdictions and paves the way fordefining a collection of TMC-to-TMC messages that support the...

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)...

The Spatial Evolution of Traffic Under the Two Wave Speed Assumption: A Shortcut Procedure and Some Observations

Daganzo, Carlos F.
1993

This paper describes the behavior of traffic in a homogeneous highway according to the hydrodynamic theory, in the special casewhere the flow-density relationship is triangular; i.e. when only two wave velocities exist. It presents an exact formula thatpredicts the vehicle that would be found at position x at time t, given the locations of all the vehicles at time zero. The formula, which does not require identification of the vehicle positions at intermediate times, automatically accounts for the creation and dissipation of any shocks. It can be used to calculate system performance...