Roads/Highways

Study of Freeway Traffic Near an Off-Ramp

Cassidy, Michael J.
Anani, Shadi B.
Haigwood, John M.
2000

A bottleneck with a diminished capacity is shown to have arisen on a freeway segment whenever queues from the segment's off-ramped spilled over and occupied its mandatory exit lane. It is also shown that longer exit queues from the over-saturate off-ramp were accompanied by lower discharge rates for non-exiting vehicles. The explanation appears to be rubber-necking on the part of the non-exiting drivers. Whenever the of-ramp queues were prevented from spilling over to the exit lane (by changing the logic of a nearby traffic signal), much higher flows were sustained on the freeway segment...

Optimized Lane Assignment on an Automated Highway

Hall, Randolph
Lotspeich, David
1996

Highway automation entails the application of control, sensing and communication technologies to road vehicles, with the objective of improving highway performance. It has been envisioned that automation could increase highway capacity by a factor of three. To attain this capacity, it will be important to minimize the amount of lane-changing and optimally assign vehicles to lanes. This paper develops and applies a linear programming based lane assignment model. The highway system is modeled as a multi-commodity network, where the commodities represent trip destinations (i.e., exit ramps on...

Simulation Modeling Of The Santa Monica Freeway

Bloomberg, Loren D.
May, Adolf D.
1994

As part of a project investigating the benefits of Intelligent Vehicle Highway Systems (IVHS) technology using simulation, two models of the Santa Monica Freeway in Los Angeles were developed. This report describes the work performed to create, test, and apply these simulations. Two independent simulations were coded, using FREQ and INTEGRATION models, from the available data. The report describes the strategies, limitations, and assumptions needed to code the Santa Monica Freeway using the two simulation tools. After coding the models, calibrating the output to match traffic performance...

A Research Plan for Highway Vehicle Navigation Technology

Gosling, Geoffrey D.
1987

This working paper describes a proposed research plan to explore the application of advanced technology to highway vehicle navigation. The proposed research addresses navigation, communication, and control technology, benefits of improved vehicle navigation, system requirements, and design and implementation issues. The paper introduces the issues involvedin highway vehicle navigation and communication, and discusses recentdevelopments in vehicle navigation technology.The importance of a vigorous program of research in this area is identified, and six near term and ten follow-on projects...

Dynamic Modeling Of Tractor-semitrailer Vehicles In Automated Highway Systems

Chen, Chieh
Tomizuka, Masayoshi
1995

This report is concerned with the dynamic modeling of the tractor- semitrailer vehicles in Automated Highway Systems (AHS). The objectives of the research are to characterize the dynamic response of articulated heavy-duty vehicles, identify the key system parameters, develop control algorithms to achieve automatic guidance, and conduct experiments on lateral guidance control of articulated heavy-duty vehicles. A modeling approach for roll, pitch and yaw motions of tractor-semitrailer vehicles is described.

Trav Info Evaluation ( Technology Element ) Traveler Information Center ( TIC ) Study: Operator Interface Analysis - Phase III

Miller, Mark
Loukakos, Dimitri
1998

TravInfo is a Field Operational Test of advanced traveler information systems for the San Francisco Bay Area, sponsored by the Federal Highway Administration (FHWA). The project involves a public/private partnership which seeks to compile, integrate and broadly disseminate timely and accurate multi-modal traveler information through commercial products and services. The public sector component centers on the Traveler Information Center (TIC), which collects and integrates both static and dynamic traveler information. The TIC began operations in September 1996 and will operate as an FOT...

Validation of the Incremental Transfer Model

Robert, Tim
Lin, Wei-Hua
Cassidy, Michael
1999

This report documents our validation effort on the Incremental Transfer (IT) model, which is a macroscopic traffic flow model capable of handling freeway systems with special lanes and priority vehicles. The validation study is performed with field data from a 1.7-mile long freeway segment with a congested off-ramp in Oakland, California. In our study, vehicles exiting the off- ramp of this segment are treated as "regular vehicles" and through vehicles as "special vehicles." By assuming that the exiting or "regular" vehicles must stay on the "near" side lanes, we examine the spatial...

Analysis Of Arterial Street Data From The ATSAC System

Bacon, Jr., Vinton W.
May, Adolf D.
1993

This study is part of an effort to simulate the Santa Monica Freeway Corridor in Los Angeles using the INTEGRATION model. The purpose of this report was to develop an efficient process of data extraction to be used for future use and to test the integrity of the data itself.

Incident Management: Process Analysis And Improvement Phase 1: Review Of Procedures

Hall, Randolph
Mehta, Yatrik
1998

This working paper examines the process for managing incidents on highways, as it is applied in Los Angeles County. The examination is based on interviews with various agencies, including law enforcement, state highway department, coroners office, and LA County MTA Freeway Service Patrol, along with direct observation through ride-alongs. Follow-up work will quantify the benefits of improved incident management, through analysis of freeway performance and response characteristics during incidents.

New Aggregation Strategies to Improve Velocity Estimation from Single Loop Detectors

Coifman, Benjamin
Lee, Zu-Hsu
2000

Loop detectors are the preeminent vehicle detector for freeway traffic surveillance. Although single loops have been used for decades, debate continues on how to interpret the measurements. Many researchers have sought better estimates of velocity from single loops. The preceding work has emphasized post-processing techniques. Although rarely noted, these techniques effectively seek to reduce the bias due to long vehicles in measured occupancy and flow. This paper presents a different approach, using a new aggregation methodology to estimate velocity and reduce the impact of long vehicles...