Field evaluation of the myrtle creek advanced curve warning system.

PDFTech ReportFHWA-OR-RD-06-13SPR 352Highway curvesTraffic control devicesEvaluationInterstate highwaysVariable message signsWarning systemsSpeed distributionMeasures of effectivenessOregonOregon. Dept. of Transportation. Research UnitBertini, Robert L.Monsere, Christopher M.Nolan, CaseyBosa, Peter G.El-Seoud, Tarek AbouOregon. Dept. of Transportation. Research UnitUnited States. Federal Highway AdministrationUS Transportation CollectionAs part of a larger study focusing on determining optimum countermeasures for speed related crashes, this report presents the results of a quantitative and qualitative before and after evaluation of a dynamic curve warning system deployed at one site on northbound and southbound Interstate 5 in Myrtle Creek, Oregon. The system displays directed messages on two dynamic message signs to drivers based on the detected speed of approaching vehicles. For the evaluation, three measures of effectiveness were selected: 1) the change in mean speed for passenger cars and commercial vehicles; 2) the change in the speed distribution for both passenger cars and trucks; and 3) public response to the dynamic message signs. Speed samples were taken of vehicles with a laser ranging and detection device, recording both speed and distance information over seven days \ue2\u20ac\u201c four in the before period and three in the after period. The quantitative evaluation indicated that the advanced curve warning system was effective in reducing the mean speeds of passenger cars and trucks by approximately 3 mph for the southbound direction and 2 mph for the northbound direction. After the system was installed, the distribution of vehicle speeds was statistically different with a lower number of vehicles in the higher speed bins. Crash reduction impacts of the system have not yet been evaluated, as the system was only recently installed. Intercept surveys of motorists at nearby rest areas revealed a positive perception of the system. Overall, the results of the evaluation indicate that the advanced curve warning system is effective