Travel Time Reliability Model for Florida

The goal of the Strategic Intermodal System (SIS) is to provide a transportation system that efficiently serves Florida's citizens, businesses and visitors: helps Florida become a worldwide economic leader, enhances economic prosperity and competitiveness, enriches quality of life, and reflects responsible environmental stewardship. Travel time reliability is widely recognized as one of, if not the, most important performance measure of highway traveler perceptions. However, determining how to measure, quantify, predict, and report reliability has proved to be elusive. Three previous Florida Department of Transportation (FDOT) research projects on travel time reliability (FDOT Contracts BD-545-48, BD-545-70, and BD-545- 75) developed and implemented models for predicting travel time reliability for freeways, using data from Philadelphia, PA, and from Ft. Lauderdale, FL. The previous projects developed a framework for calculating travel time reliability for a freeway section in South Florida (I-95 / SR 9 between Broward Blvd. and Sunrise Blvd.) The objectives of this project were to (a) refine the previously developed framework and travel time estimation models to evaluate the impacts of various Intelligent Transportation Systems (ITS) applications on travel time reliability, (b) continue to assess the use of field data across Florida to refine the current model, and (c) apply the refined model to the entire SIS freeway system. The methodology and example spreadsheets previously developed were updated to consider incident durations longer than one hour. Also, various ITS strategies (including the Road Rangers program) were evaluated and recommendations were formulated on how the impacts of these strategies can be incorporated into the travel time reliability estimation method. The freeway portion of the SIS was segmented and various measures of travel time reliability were obtained for each section of the system. The geometric information for the network, hourly demands, and expected frequency of congestion for each hour was derived from the FDOT Roadway Characteristics Inventory (RCI) database.