Traffic Operations and Management

Traffic Management Systems Performance Measurement: Final Report

Banks, James H.
Kelly, Gregory
1997

This report documents a study of performance measurement for Transportation Management Centers (TMCs). Performance measurement requirements were analyzed, data collection and management techniques were investigated, and case study traffic data system improvement plans were prepared for two Caltrans districts.

Driving Safely in Smart Cars

Puri, Anuj
Varaiya, Pravin
1995

This paper considers the issue of safety in Automated Vehicle Highway Systems (AVHS). An approach is proposed for proving that a system is safe. The design for a proposed AVHS is considered and shown that if the physical controllers in the vehicles satisfy a set of constraints then the AVHS is safe. The authors contend that the problem of checking whether the controllers satisfy the constraints is equivalent to solving an optimal control problem.

Development of Integrated Meso/Microscale Traffic Simulation Software for Testing Fault Detection and Handling in AHS

Horowitz, Roberto
2004

In this report, we describe the research carried out under PATH Task Order 4208. The objective of this project was to bridge the gap between the Automated Highway System (AHS) simulators SmartAHS and SmartCAP, by implementing an integrated AHS micro-meso simulation environment for analyzing a large-scale AHS network. In fulfillment of this goal, a meso-microscale traffic simulator was developed that allows a stationary region of microsimulation to be defined within a larger, mesosimulated AHS. This simulator permits analysis of traffic behavior in situations where both vehicle-level (...

Identifying Density-Flow Relations on Arterial Surface Streets

Ahn, Soyoung
Cassidy, Michael J.
2002

A simple car-following rule was verified by studying vehicles discharging from long queues at signalized intersections. These observations indicated that the time-space trajectory of a jth vehicle discharging on a homogeneous intersection approach was essentially the same as the j−1th vehicle except for a translation in space and time. This is in agreement with a simplified theory proposed by G.F. Newell. The finding indicates that the congested branch of a density-flow curve is linear in form.

A Comparison of Traffic Models: Part 1, Framework

Lo, Hong K.
Lin, Wei-hua
Lawrence, C.
Chang, Elbert
Tsao, Jacob
1996

This report defines a framework for comparing dynamic traffic models. It emphasizes four dimensions: functionality, traffic dynamics, route choice dy namics, and overall network performance. The first dimension compares the models through a check-list of model functions. Regarding the last three comparison dimensions, a total of five networks and twelve scenarios are defined. These test scenarios are designed to accentuate model properties and differences. Also included in the report are a list of performance measures for comparison purpose, and a discussion of the interpretation of...

Bay Area Simulation and Ramp Metering Study - Year 2 Report

Gardes, Yonnel
Kim, Amy
May, Dolf
2003

As part of the California PATH program, the Paramics microscopic traffic simulation model was evaluated through a pilot application to the I-680 freeway corridor, one of the most highly congested facilities in the San Francisco Bay Area. The main objective of the project was to test the capability of the model to serve as a tool for evaluating alternative transportation planning and traffic management scenarios. HOV lanes were investigated first on a "simple" network, and later on the existing I-680 corridor. An Application Programming Interface (API) "plugin" designed by Quadstone, which...

Evaluation of On-Ramp Control Algorithms

Zhang, Michael
Kim, Taewan
Nie, Xiaojian
Jin, Wenlong
Chu, Lianyu
Recker, Will
2001

The control of a traffic corridor, which consists of two major component - freeway system control and arterial street system control, aims to improve flows on both freeway and arterial streets, and has been demonstrated as an effective means to increase the level of service of a corridor system during peak periods. Ramp metering, or ramp control, has been considered to be a very important component of corridor traffic control. Ramp metering is the application of control devices such as metering signals to limit the number of vehicles entering a freeway. The fundamental philosophy of ramp...

Assessment of MeMS Sensors in an Urban Traffic Environment

Varaiya, Pravin
2004

The objective of this "innovative new research topics" proposal was to investigate the potential of a vehicle detection system that combines an acoustic or magnetic sensor, a microprocessor, a radio, and a battery. If such a system is feasible, it would be a low-cost, flexible alternative to loop detection systems. The wireless sensor system could be installed in a few minutes, without the expensive loop installation that requires cutting the pavement, power and loop cabling, and extended traffic disruption. Four tasks were proposed: (1) detecting a stationary vehicle, (2) detecting a...

SafeTrip 21 Initiative: Networked Traveler Foresighted Driving Field Experiment Final Report

Nowakowski, Christopher
Gupta, Somak Datta
Sengupta, Raja
Mannasseh, Christian
Spring, John
VanderWerf, Joel
Sharafsaleh, Ashkan
Vizzini, Daniel
2011

This report describes the SafeTrip-21, Networked Traveler Foresighted Driving Field Experiment conducted as part of the US DOT’s SafeTrip-21 initiative. This experiment developed and evaluated an Advanced Driver Assistance System providing soft-safety or situational awareness alerts regarding “Slow Traffic Ahead” when driving on a freeway. The Networked Traveler system detects slow traffic or queues at several thousand locations in the Bay area, monitors the locations and speeds of its test subjects as they drive, and determines if the driver is approaching the slow traffic fast enough to...

Optimizing Comprehension of Changeable Message Signs (CMS)

Greenhouse, Daniel
2007

The goal of this research was to assist the California Department of Transportation (DOT) in optimizing the message content and presentation within changeable message signs (CMS). Optimized content will improve information transfer while at the same time minimizing the likelihood of congestion owing to slowing by motorists attempting to read the message. The research was restricted to simulated signs displaying 16 characters in each of three lines, representing permanent CMS displays, or signs containing only 8 characters in each of three lines, as is the case for portable CMS displays....