Traffic Operations and Management

TRACER: In-vehicle, GPS-based, Wireless Technology for Traffic Surveillance and Management

McNally, M. G.
Marca, J. E.
Rindt, C. R.
Koos, A. M.
2003

The fundamental principle of intelligent transportation systems is to match the complexity of travel demands with advanced supply-side analysis, evaluation, management, and control strategies. A fundamental limitation is the lack of basic knowledge of travel demands at the network level. Modeling and sensor technology is primarily limited to aggregate parameters or micro-simulations based on aggregate distributions of behavior. Global Positioning Systems (GPS) are one of several available technologies which allow individual vehicle trajectories to be recorded and analyzed. Potential...

Monitoring The San Francisco Bay Area Freeway Network Using Probe Vehicles And Random Access Radio Channel

Linnartz, Jean-paul M. G.
Westerman, Marcel
Hamerslag, Rudi
1994

In this report, the authors describe a method of collecting real-time traffic data from probe vehicles automatically sending traffic reports to one or m ore base stations, connected to a traffic center by a wired communications network. Analyzing and computing road traffic and message traffic flows in the San Francisco Bay Area, the authors study several multi-disciplinary aspects of this data collection technique. The results presented in this report reveal that random access (ALOHA) transmission of traffic messages is a (spectrum) efficient, inexpensive and flexible method for collecting...

Development and Assessment of Selected Mobility Applications for VII: Principal Findings

Shladover, Steven E
Lu, Xiao-Yun
Nowakowski, Christopher
2011

This project has shown how connected vehicle systems, based on vehicle-vehicle and vehicle-infrastructure communication and coordination, can support the development of mobility-enhancing applications with the potential to transform the performance of the road transportation system. Three separate mobility-enhancing applications were developed, simulated, and tested, and their expected mobility benefits were estimated using simulations. Cooperative adaptive cruise control was shown to have a high potential for user acceptance, and when applied at the gap settings chosen by representative...

SPRINTER Rail: Grade Crossing/ Traffic Signal Optimization Study

Wu, Guoyuan
Li, Irene
Zhang, Wei-Bin
Johnston, Scott
Li, Meng
Zhou, Kun
2009

The second phase of this project further investigates impacts to local traffic operations at intersections adjacent to signal preemption by SPRINTER commuter trains and comes up with countermeasures that not only minimize such impacts but also take into account the traffic signal coordination. An extended traffic signal optimization model has been developed to minimize overall traffic delays and the weighted width of “green band” along several coordinated traffic signals around the grade crossings. Based on the train’s movement detection at grade crossings and the waiting queue estimation...

Design, Field Implementation and Evaluation of Adaptive Ramp Metering Algorithms

Horowitz, Roberto
May, Adolf
Skabardonis, Alex
Varaiya, Pravin
Zhang, Michael
Gomes, Gabriel
Munoz, Laura
Sun, Xiaotian
Sun, Dengfeng
2005

The main objectives of Task Order 4136 are (1) the design of improved freeway on-ramp metering strategies that make use of recent developments in traffic data collection, traffic simulation, and control theory, and (2) the testing of these methods on a 14-mile segment of Interstate 210 Westbound in southern California. To date, the major accomplishments of this project include (i) the development of a complete procedure for constructing and calibrating a microscopic freeway traffic model using the Vissim microsimulator, which was applied successfully to the full I-210 test site, (ii) a...

Providing In-Vehicle Soft Safety Alerts Using Mobile Millennium Data and Vehicle Event Information

Nowakowski, Christopher
Gupta, Somak Datta
Myers, Scott
Shladover, Steven
Butler, Joe
Bayen, Alex
2012

The Mobile Millennium project provided a platform for aggregating traffic information across various sources, including infrastructure sensors, commercial data feeds, probe vehicles, and probe cell phones. The Networked Traveler project provided the California PATH instrumented research vehicle platform used to both deliver vehicle probe data back to the infrastructure and to generate Advanced Driver Assistance Systems (ADAS) alerts to the drivers of those vehicles. The main theme of this collaboration project was to demonstrate the potential to create Enhanced Probe Vehicles (EPVs) by...

Using Cooperative Adaptive Cruise Control (CACC) to Form High-Performance Vehicle Streams. Microscopic Traffic Model Calibration and Validation

Kan, Xingan (David)
Liu, Hao
Shladover, Steven E.
Lu, Xiao-Yun
2018

This report documents the procedures the PATH team has implemented for calibrating the NGSIM oversaturated flow model in the Aimsun micro simulation environment. The goal of the calibration is to identify suitable driving behavior parameters of the NGSIM oversaturated flowmodel, which is used to describe the behaviors of human drivers. With these parameters, the model should be able to reproduce traffic flow patterns like those observed in the 18-km State Route 99 corridor to the south of Sacramento, CA. The Geoffrey E. Havers (GEH) statistic is adopted to quantify the relative difference...

Evaluation of Traffic and Environment Effects on Skid Resistance and Safety Performance of Rubberized Open-grade Asphalt Concrete

Oh, Soon Mi
Ragland, David R.
Chan, Ching-Yao
2010

Wet pavement-related collisions represent a significant traffic safety concern, due in part to the lack of adequate friction between tire and pavement, known as skid resistance. State agencies employ a skid number (SN) system, based on a standard test procedure in which a locked wheel is towed at 40 mph and the skid number (SN40) is calculated from the measured resistance. SN40 is used as a reference value for speeds both greater than and less than 40 mph. For most Departments of Transportation (DOTs) in the nation, excluding California, pavements for which the SN40 is below 30 are deemed...

Improving Mobility Through Enhanced Transit Services: Case Studies for Transit-Taxis

Widmann, Joshua H.
Miller, Mark A.
2006

This report, an interim deliverable for Task Orders 5408 and 6408: “Improving Mobility through Enhanced Transit Services”. Thus far in the study we have performed a review of the literature and conducted a small number of site-specific case studies for transit agencies in North America identified from the literature review as either currently having or in the past having had transit-taxi service implemented in their agency’s jurisdiction. We initially classified alternative concepts of transit-taxis into a typology of three service design options based on a review of the literature: 1)...

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.