Modeling

Travel Time Estimation on the San Francisco Bay Area Network Using Cellular Phones as Probes

Ygnace, Jean-Luc
Drane, Chris
Yim, Y. B.
de Lacvivier, Renaud
2000

Current traffic travel time estimates are largely based on road sensors embedded in the pavement. Today technical developments in cellular positioning and the spread of wireless phones provide the opportunity to track cell phone equipped drivers as traffic probes. The Federal Communication Commission Phase II mandate for Enhanced-911 (E-911) requires that wireless carriers must provide the location of a 911 wireless call by October 1, 2001 to the Public Safety Answering Point (PSAP), within approximately 125 meters, or under one-tenth of a mile in the majority of situations. The motivation...

A Comparison of Traffic Models: Part II Results

Lo, Hong K.
Lin, Wei-Hua
Liao, Lawrence C.
Chang, Elbert
Tsao, Jacob
1997

This working paper is the second part of a series comparing dynamic traffic flow models. It documents the results of comparison based on the framework defined in Part 1. The traffic models selected for comparison are DINOSAUR, DYNASMART, INTEGRATION, and METS. The areas of comparison comprise four categories: functionality, traffic dynamics, route choice mechanism, and network performance.The first category was compared with a checklist of functions. A total of thirteen test scenarios were constructed to compare models for the last three categories.

Traveler Response to New Dynamic Information Sources: Analyzing Corridor and Area-Wide Behavioral Surveys

Yim, Youngbin
Khattak, Asad J.
Raw, Jeremey
2004

Intelligent Transportation Systems present a well-known innovation opportunity to address urban congestion and allow greater access to transportation networks. New sources of travel information are emerging rapidly and they are likely to significantly impact traveler decisions and transportation network performance. To assess the value and impact of these new sources, this paper develops a comprehensive conceptual model based on information processing and traveler response. Specifically, the model accounts for the effect of information source, content and quality on information access and...

A Probabilistic Model And A Software Tool For AVCS Longitudinal Collision/safety Analysis

Tsao, H. S. Jacob
Hall, Randolph W.
1993

This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to failure, the reaction delay of the following vehicle and a bivariate joint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time. The model is used to compare the safety consequences associated with the platooning and "free-...

Dynamic Traffic Assignment For Automated Highway Systems: A Two-lane Highway With Speed Constancy

Tsao, H. S. Jacob
1996

Dynamic traffic assignment through analytical modeling and optimization has been widely accepted by the IVHS R&D community as a promising traffic control tool for understanding and relieving traffic congestion on conventional highways and city streets. Due to the completely controlled nature of AHS traffic, dynamic assignment of AHS traffic is even more promising. One added dimension of complexity associated with AHS dynamic traffic assignment is lane assignment. Lane changes, for fully utilizing AHS capacity or for exiting, incur disturbances to and hence reduction of longitudinal...

Vehicle Modeling and Verification of CNG-Powered Transit Buses

Hedrick, J. K.
Ni, A.
2004

This report will present the results of the initial study to develop an accurate working model of the 40 foot New Flyer Bus powered by the Cummins C8.3+ 280G CNG engine (Figure 1.1). The main focus of the study is the modeling of the vehicle dynamics using step input acceleration data. Other parts of the research include gear shifting and torque production from the CNG engine, all of which are required to produce a completely simulationcapable bus model.

A Link-Based Variational Inequality Model for Dynamic Departure Time/Route Choice

Ran, Bin
Hall, Randolph
Boyce, David E.
1995

The dynamic user-optimal (DUO) departure time and route choice problem is to determine travelers’ best departure times and route choices at each instant of time. In a previous paper, we presented a route-based two-level optimal control model for the DUO departure time/route choice problem. However, this model is not appropriate for large scale transportation networks because some degree of route enumeration is necessary to solve the model. In this paper, we present a link-based variational inequality (VI) formulation for the DUO departure time/route choice problem so that route enumeration...

Institutional, Organizational and Market Aspects of Successful ITS Deployment: A Case Study Analysis

Conroy, Patrick
2003

This research follows on a previous study to explore key aspects of successful Intelligent Transportation Systems (ITS) deployment within existing institutional, organizational and market environments. The researcher developed three additional case studies of successful ITS deployment in the U.S. and Europe, and revisited one case from the previous work. Results from literature searches and surveys were analyzed, and findings on institutional, organizational and market factors are presented. Key words: ITS, deployment, institutional, value, business models, benefits, highway capacity

Integrated Traffic and Communications Modeling Environment for ATMIS

Varaiya, P.
Walrand, J.
Wu, F.F.
Polydoros, A.
Sylvester, J.
1997

The aims of this MOU were to create an integrated environment for modeling traffic flow, sensor data, and the communications infrastructure for ATMIS. The research plan was to build separate tools for measuring the communications requirements of ATMIS traffic, modeling a mobile radio communications environment, and communications network design, and then to integrate them in an object-oriented environment from which one could also access existing or new road traffic simulation packages.Section 1 of the report presents a framework for estimating the vehicle-roadside communications...

PATH ITS Research Digests

Chira-Chavala, Ted
2001

Ramp meters are commonly used to relieve congestion on freeways. What is the value of these systems? Ramp metering can alleviate recurrent, regular traffic congestion, such as that caused by the daily commute. The goal is usually to maintain uninterrupted freeway flow at a certain acceptable level, but it transfers delay to the entrance ramp, where excess demand is forced to wait. This report summarizes ramp metering technologies, reviews the algorithms commonly used with them, and uses a traffic simulation model to identify the benefits and costs of using these systems. We used a...