Contracting Agency: Florida Department of Transportation (FDOT) Principal Investigator: Scott Washburn, Ph.D.
Lane closures during roadway repairs can inconvenience travelers and impact local economies by delaying commercial vehicles. The Florida Department of Transportation (FDOT) was interested in updating the methodologies it uses for planning lane closures on two-lane and arterial roadways. FDOT asked the Transportation Research Center at the University of Florida to conduct a three-part study to develop the new models. Because there was no data available from field studies of lane closures like these, the researchers used simulation to generate data for use in developing the models.
For Part I, because of a lack of a suitable simulation program for modeling lane closures on two-lane, two-way roadways, a custom simulation program was created, called FlagSim. This program was used to develop analytic models for estimating work zone travel speed, saturation flow rate, queue delay, and queue length for lane closures on two-lane roadways. The analytic models have been incorporated into a comprehensive analysis spreadsheet that will replace the current analysis method contained in the PPM. FlagSim is also available for use in studying issues beyond the scope of the analysis spreadsheet, such as non-standard vehicle performance characteristics, different flagging methods, or oversaturated traffic conditions.
Part II focused on developing capacity models for arterials with lane closures near a traffic signal. The CORSIM simulation program was used to develop traffic capacity models for five different arterial work zone configurations. The models are ready to be tested on existing and planned work zone closures so that field data can be collected and the models validated. The models will need modification in order to consider the impact of additional factors such as roadway geometry.
The lane closure analysis procedure currently in use by FDOT requires an estimate of normal hourly traffic demand, called the “Remaining Traffic Factor” (RTF), in proposed work zones. The purpose of Part III of this study was to develop models for estimating the RTF. A survey of drivers to determine if they would use other routes to avoid work zone areas revealed that travel time, work zone location, and weather conditions would influence their decisions. With these data, the researchers developed models for estimating RTF in both short- and long-term work zones, which are implemented in a spreadsheet tool.
Once tested and verified, these models will be used to develop work zone plans that should result in reduced impacts to motorists.
Transportation Research Center Lily Elefteriadou, Ph.D., TRC Director
University of Florida Civil & Coastal Engineering
512 Weil Hall | PO Box 116500 | Gainesville, FL 32611-6580
352.392.9537, Ext. 1409