Freeway Service Patrol Programs Research Articles

Analysis of freeway service patrol with discrete event-based simulation

As an efficient incident management program, freeway service patrol has gained wide popularity. There is increasing need for developing systematic procedures of planning the program to ensure efficient resource allocation and to achieve maximum benefits. A discrete event-based simulation model is developed to replicate the patrol process that includes districting, incident generation, response vehicle dispatching and routing, and incident clearance. Model validation proves its capability to accurately replicate the incident generation/distribution process. Later, the Interstate-95 freeway in south Florida is used as a model application example to test alternatives, and the improved alternative shows better performance compared with the previous even-length districting method and the currently used even-activity districting approach. Besides traditional roving scheme, the simulation model also has the capability to evaluate the prepositioning schemes. Furthermore, sensitivity analysis is performed to examine the impact of operational parameter settings, such as beat districting, incident detection rate, and incident frequency. Although continuous efforts are needed to develop a more comprehensive simulation model for the freeway service patrol program, the application example presented in this study reveals promising application results, and provides an insight into the patrol process as well as a better understanding of the impact of parameters on performance.

A simulation approach for quantifying the cost-effectiveness of freeway service patrols programs

Freeway Service Patrols is one of the main components of highway Incident Management (IM) programs because of its low-cost feature and effectiveness in incident detection, mitigation and clearance. This paper presents a methodology to quantify freeway service patrol programs' cost-effectiveness with limited operation data using microscopic simulation. Simulation models are developed to test benefits of patrol service by comparing 'with' and 'without' scenarios under various traffic conditions. The analysis results from a case study indicate that patrol operations may have a significant impact on incident detection process, especially for incidents of low severity, such as debris and abandoned vehicles.

Simulation Model for Evaluating and Improving Effectiveness of Freeway Service Patrol Programs

Nonrecurrent congestion caused by highway incidents is a major concern for transportation agencies and millions of road users in most metropolitan areas in the United States. As a low-cost approach to incident management, freeway service patrol programs have gained wide popularity. Although there are many such programs in different parts of the country, there is not much effort to design such programs systematically so that better results can be obtained through efficient use of existing resources. A simulation model has been developed that can be used for designing a new freeway service patrol program configuration as well as improving operations of existing programs. The Hoosier Helper program in northwest Indiana is presented as an example of the model’s application. The information provided in this study would be useful for evaluating and improving the effectiveness of similar patrol programs in other metropolitan areas in Indiana and in other states.

ITS Impacts on Safety and Traffic Management: An Investigation of Secondary Crash Causes

Freeway service patrols, an increasingly popular choice in combating the effects of traffic incidents on freeway operations, have been known to reduce incident response and clearance time. This reduction can help alleviate the delay due to non-recurrent, incident related congestion, as well as lower the chance of secondary crashes. While much work has been done in the direction of identifying the benefits stemming from the delay savings by freeway patrols, little has been done to identify the potential savings from lowering the likelihood of secondary crash occurrence. Using a 5-year incident data base from the Borman Expressway, we develop logistic regression models to examine what primary crash characteristics are likely to influence the likelihood of a secondary crash. The findings suggest that clearance time, season, type of vehicle involved, and lateral location of the primary crash significantly influence the likelihood of secondary crash occurrence. Further, the 1995 potential benefit from secondary crash reduction was $568,080 exceeding the 1995 Hoosier Helper freeway service patrol program costs by a factor of 1.38. Given a better understanding of what contributes to secondary crash occurrence, various components of incident management can be operated at a higher level of cost-effectiveness.

Investigation of Freeway Incident Characteristics and Their Influence in Planning an Incident Management Program

Nonrecurrent congestion caused by highway incidents is a major concern for transportation agencies and millions of road users in most metropolitan areas in the United States. Incidents account for 60 percent of congestion-induced delay. As a low-cost approach to incident management, freeway service patrol programs have gained wide popularity. However, information on freeway incident characteristics is limited. In the current paper, incident data recorded by the Hoosier Helper program in north-west Indiana is analyzed. The distributions of incident frequency and clearance time by incident type and lateral location are reported. The variation of incident rate with time of the day is examined, and the influence of various factors affecting the frequency and clearance time of incidents is explored. Recommendations are made to improve the freeway service patrol program, based on the incident data analyzed. The information provided in this study may be useful for planning similar patrol programs in other metropolitan areas in Indiana and other states.

Freeway Service Patrols: A State of the Practice

Freeway service patrols have been cited as one of the most effective elements of an incident management program for reducing incident detection time and incident duration. Service patrol programs utilize roving vehicles to patrol congested and high incident sections of urban freeways. The state of the practice of freeway service patrol programs in the United States is documented in this paper. A telephone survey was conducted with managers of 53 freeway service patrols in 22 states. Approximately 74 percent of the surveyed service patrols are sponsored exclusively by public agencies. Approximately 47 percent of the surveyed patrols are sponsored exclusively by Department of Transportations; 6 percent are sponsored exclusively by police agencies; and 21 percent are sponsored by multiple public agencies. Approximately 34 percent of the patrols receive federal support funding. Finally, 27 percent of the patrols operate with private funding sources. Service patrol hours of operation vary from program to program, with the most common being coverage of the weekday a.m. and p.m. peak periods. Approximately 70 percent of the surveyed agencies own and operate their own vehicles, whereas 26 percent contract with private tow companies to provide drivers and vehicles. Benefits associated with service patrols are typically quantified by multiplying a value of time by the estimated delay reduction provided by the service patrol in vehicle-hours. Available benefit to cost analyses for 15 of the service patrols studied ranged from 2:1 to 36.2:1. A contact list and recommendations for agencies interested in starting a new service patrol program are also included in this paper.

The freeway service patrol evaluation project: Database support programs, and accessibility

This paper discusses the Freeway Service Patrol (FSP) Evaluation Project conducted under the California PATH program. The goal of this project was to determine the cost effectiveness of the FSP program along a 10-mile “beat” on I-880, near Hayward, California. We collected data from three different sources: loop detector data, probe vehicle data and incident log data. We describe these sources in detail and the problems that were encountered with them. We also discuss the support programs developed to process this data, and the efforts to place the data and the programs on-line for use by researchers around the country.