Analyzing the Synergistic Effects of TSMO Strategies for Quicker Speed Recovery After Incidents

Abstract: Transportation Systems Management & Operations (TSM&O) strategies are operational techniques designed to optimize transportation network performance, improve traffic flow, and enhance safety, especially during incidents or peak traffic periods. TSM&O strategies include Dynamic Message Signs (DMSs), Road Ranger Service Patrols (RRSP), Severe Incident Response Vehicles (SIRV), and Express Lanes (ELs), among others. DMSs provide real-time communication to drivers about incidents and roadway conditions. RRSPs assist with minor incidents by providing roadside help, changing tires, and clearing debris. SIRVs are specialized units for severe incidents like major crashes or hazardous spills. The key difference between RRSPs and SIRVs lies in their scope: RRSPs manage routine disruptions, whereas SIRVs handle severe incidents, such as multi-vehicle crashes, full highway closures, or hazardous material spills. ELs are toll lanes offering faster, reliable travel with dynamic toll adjustments.

In South Florida, various TSM&O strategies are deployed to manage traffic incidents. While these strategies have independently demonstrated safety and operational benefits, there is a lack of evidence-based procedures for their synergistic deployment to ensure quicker speed recovery after an incident. This study addressed this gap by evaluating the combined effects of TSM&O strategies on traffic speed recovery following incidents.

This study analyzed traffic data from 2020 to 2022, focusing on the I-95 corridor in South Florida, spanning Broward, Palm Beach, and Treasure Coast counties. The main objective was to identify the most effective combinations of DMS, RRSP, SIRV, and ELs in facilitating quicker speed recovery after incident. A data-driven approach was employed, using speed exceedance probability analysis to quantify recovery across various time intervals following incidents. The data incorporated weather conditions, speed measurements, incident specifics (including the presence or absence of RRSP and SIRV), and the operational status of ELs. Data sources included SunGuideTM for incident data, the National Oceanic and Atmospheric Administration (NOAA) for weather data, the Regional Integrated Transportation Information System (RITIS) for speed data, and the Florida Department of Transportation (FDOT) for TSM&O operational records. The methodology involved integrating data from multiple sources to assess different combinations of the TSM&O strategies during both minor and major incidents.

Results show that the integrated deployment of RRSP, SIRV, and ELs yields the highest probabilities of quick speed recovery, particularly within 5-30 minutes after incident clearance. The combination of all three strategies significantly reduces post-incident delays, with a probability of speed recovery exceeding 70% within the first 5 minutes of clearance for minor incidents and within 15 minutes for major incidents. Additionally, the use of DMSs across all scenarios contributed to more efficient communication with drivers, further enhancing recovery times.

The study concluded that a coordinated and integrated approach involving DMS, RRSP, SIRV, and ELs optimized traffic recovery, reduced congestion, and improved overall network performance. The findings provided evidence for transportation agencies to adopt integrated TSM&O strategies, during peak traffic periods, and enhance the safety and resilience of the transportation network. This study also established a framework for the development of advanced, adaptive traffic management systems that leveraged real-time data to improve incident response and recovery.