Travel Time Reliability Models for Freeways and Arterials; Final rept

摘要

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. A previous FDOT research project on travel time reliability reviewed and recommended a travel time reliability definition to be used by FDOT. It also developed models for estimating travel time reliability on freeways based on field data from Philadelphia, PA. The research summarized in the report focused on (1) modifying and adjusting the previously developed models for freeways with Florida data; (2) using FDOT databases to report travel time reliability for freeways throughout Florida; (3) developing a preliminary framework for reporting travel time reliability on arterials. The report presented the data obtained from Florida and the analyses conducted to estimate travel time reliability, including flow and speed data, as well as incident and weather information. The database requirements for obtaining travel time reliability in Florida were provided, along with an assessment of existing FDOT databases for estimating travel time reliability for the SIS. The report also provides a literature review on arterial travel time estimation, along with a preliminary framework for estimating travel time on arterials. The research concluded the following: (1) There are several systems being installed in Florida for monitoring various performance measures, including speeds, travel times and incidents. These systems are still being tested and calibrated, therefore this research could not use field data from Florida to recalibrate the existing models developed under FDOT Contract BD-545, RPWO no. 48. (2) The incident information data obtained from District 4 appear to be of good quality; however, there are some inconsistencies observed in the reporting for certain performance measures. (3) Weather information can be obtained relatively easily across Florida; however, the analysis can be time-consuming depending on the sampling interval in terms of time, as well as in terms of space (i.e., the number of stations examined across Florida).