Data

Application of Fuzzy Logic and Neural Networks to Automatically Detect Freeway Traffic Incidents

Hsiao, Chien-Hua
Lin, Ching-Teng
Cassidy, Michael
1994

To date, efforts to manage freeway congestion have been seriously impeded by the inability to promptly and reliably detect the presence of traffic incidents. Traditional incident‐detection algorithms distinguish between congested and uncongested operation by comparing measured traffic‐stream parameters with predefined threshold values. Given the range of possible operating conditions in the traffic stream, selecting a single threshold value, and the suitability of that selected threshold, is full of uncertainty. This inherent uncertainty makes fuzzy logic a promising approach to...

Middleware for Cooperative Vehicle-Infrastructure Systems

Manasseh, Christian
Sengupta, Raja
2008

Middleware has emerged as an important architectural component in supporting distributed applications. The role of middleware is to present a unified programming model to application writers and to mask out problems of heterogeneity and distribution. Mobile sensors fall into the space of distributed systems that suffer from isolated data sources, heterogeneous communication infrastructure and varying application requirements. In this report, we provide a middleware architecture that addresses the needs of a distributed system made of mobile sensors in general and discuss the implementation...

Modeling The Santa Monica Freeway Corridor: A Feasibility Study

Skabardonis, Alexander
Dahlgren, Joy
May, Adolf D.
1998

This report presents the findings of a feasibility study which developed a simulation testbed for the Santa Monica freeway corridor. The study involved performing an evaluation of the state-of-the-art models for Advanced Traffic Management and Traffic Information Systems (ATMIS) on freeway corridors. The evaluation was based on the model capabilities, input data requirements and output options, with focus on the record of real-life calibration, validation and practical application of the models. The findings show that the CORSIM and INTEGRATION models have the higher probability of...

Traffic Data Measurement and Validation

Coifman, Benjamin
2001

Caltrans collects traffic data for many monitoring and control applications and the ultimate goal of the traffic surveillance system is to provide accurate data to these high level applications. The surveillance system includes data measurement, averaging and verification algorithms. This report presents improvements to many elements of the surveillance system. First, section 2addresses many shortcomings in average speed estimation at single loop detectors, as well as other sensors that estimate speed from average flow and occupancy. At the root of these problems is the fact that the...

Assessing the Benefits and Costs of ITS Projects: Volume 1 Methodology

Gillen, David
Li, Jianling
Dahlgren, Joy
Chang, Elva
1999

In this document a framework for evaluating ITS projects is developed. One of the central issues addressed is whether ITS projects are distinctly different from other more conventional transportation projects and thus the traditional decision methods such as Benefit-cost analysis cannot be used. The answer is mixed. The decision models used in the past are still relevant, however, these have been applied in an environment in which there was a well developed data base. The models identified, selected, assembled and evaluated data to make judgements as to whether the proposed projects were...

Health of California’s Loop Detector System

Rajagopal, Ram
Varaiya, Pravin
2007

The California Department of Transportation (Caltrans) freeway sensor network has two components: the sensor system of 25,000 inductive loop sensors grouped into 8,000 vehicle detector stations (VDS) and covering 30,500 freeway direction-miles; and the communication network over which the sensor measurements are transported to Caltrans Traffic Management Centers. The sensor network is virtually the only source of data for use in traffic operations, performance measurement, planning and traveler information. However, the value of these data is greatly reduced by the poor reliability of the...

Experimental Verification of Discretely Variable Compression Braking Control for Heavy Duty Vehicles

Vahidi, Ardalan
Stefanopoulou, Anna G.
Farias, Phil
Tsao, Tsu Chin
2003

In this report a recursive least square scheme with multiple forgetting factors is proposed for on-line estimation of road grade and vehicle mass. The estimated mass and grade can be used to robustify many automatic controllers in conventional or automated heavy-duty vehicles. We demonstrate with measured test data from the July 26-27, 2002 test dates in San Diego, CA, that the proposed scheme estimates mass within 5% of its actual value and tracks grade with good accuracy. The experimental setup, signals, their source and their accuracy are discussed. Issues like lack of persistent...

Long Term Impacts of California’s Graduated Licensing Law of 1998

Cooper, Douglas
Gillen, David
2005

In July 1998 California changed its graduated driver licensing laws (GDL) for new drivers under the age of 18 to include restrictions on hours of driving, carrying teen-age passengers, and requiring more adult supervised driving practice. With fatal and injury crash data from California's Statewide Integrated Traffic Records System, this study, sponsored by Caltrans, used standard regression analysis as well as the Bai-Perron stochastic multiple structural break model to determine the effect of the law on teen-age passengers and crash rates of 16 year-old drivers. We found that in the four...

Weaving Analysis, Evaluation and Refinement

Skabardonis, Alexander
Kim, Amy
2010

Weaving sections are common design elements on freeway facilities such as near ramps and freeway to-freeway connectors. When the traffic demands exceed the capacity at weaving areas congestion may occur, which affects the operation of the entire freeway section. Traffic operational problems also may exist at weaving areas even when traffic demands are less than capacity because of the complexity of vehicle interactions, resulting in poor level of service (LOS) and potential safety problems. Existing procedures for the design and analysis of freeway weaving sections have several...

Buscando la Piedra Rosetta de los Puntos de Función

Cuadrado-Gallego, JJ
Dolado, J
Rodriguez, D
Sicilia, MA
2016

La importancia adquirida por los puntos de función se puede constatar tanto en la enorme difusión de su aplicación, como en la diversidad de los métodos desarrollados, o en la estandarización de dichos métodos. Este último aspecto, la generación de esta diversidad de métodos de medición, ha introducido fundamentalmente dos factores de dificultad a la hora de utilizar puntos de función, como son, por una parte, la comparación de medidas realizadas con diferentes métodos, y por otra la elección del método más adecuado para el usuario y el proyecto. Este artículo presenta los resultados de un...