Rural Data Collection Technology - FHWA Operations - U.S. ...

supports efforts to distribute ITS deployments wherethey are most needed.On rural freeways, WisDOT captures travel time datausing sidefire microwave detectors. RTT coverageis provided in the vicinity of the I-90/I-94 split nearTomah, WI (see Figure 12) on the I-94 corridorbetween Milwaukee and Madison (see Figure 12), anda portion of US-41 between Milwaukee and GreenBay. WisDOT has been implementing these traveltime deployments for about 7 years. Prior to sidefireradar, WisDOT used loop detectors as its primarysource of travel time data, then shifted to microwavedetection. Microwave detection was preferred overloop detectors and eventually became standardpractice because it was easier to maintain andreplace, with the particular benefit of not requiringlane closures and invasive pavement work.WisDOT experience shows that rural travel times varyinfrequently unless there is a traffic incident. The RTTsystem, however, is not intended specifically for useas an incident detection system and does not includeany features for automatic incident detection; WisDOTgenerally learns of incidents first from police reports.WisDOT provides DMS showing travel times onsome rural routes. In a non-scientific survey,about 80 percent of drivers stated a preferencefor messages that show both travel time andFigure 12Examples of Rural Freeway Travel Time Coverage in WisconsinSource: 511wi.comRural Data Collection TechnologyFederal Highway Administration29