Hanson, Zach

Mobile RWIS technologies are still relatively new to the market, with only a few early-adopting agencies deploying them, primarily in testing situations. This study provides a comprehensive and comparative analysis of four commercially available mobile RWIS sensors. The sensors in the study include: Lufft’s MARWIS, Teconer’s RCM411, High Sierra’s Mobile IceSight, and Vaisala’s DSP310. Testing was completed in two phases. Phase I focused on the accuracy of different sensor parameters when compared to a known baseline. These tests took place at the MnROAD testing facility, a test track containing a variety of pavement types operated by the Minnesota Department of Transportation. Phase II was conducted in “real-world” settings on active roadways. Sensors measured the environment along a set route in live traffic in a variety of weather conditions. The study compared the sensors’ performance while measuring air temperature, surface temperature, relative humidity, surface condition, water film thickness, and friction. The evaluation also compared qualitative aspects of the sensors such as installation methods. The project found that overall, sensors performed similarly across all parameters. This report ranks sensors by accuracy, but the absolute differences in values used to determine rank are often very small. The study also developed standardized recommendations for various mobile sensor parameters. While differences across sensors and the high variability in their readings make establishing universal standards difficult, some commonalties were found. The report includes a suggested matrix of a few basic levels categorizing grip, surface state, and mobility impact. Project completed for Clear Roads Pooled Fund program, #TPF-5(353).

The Minnesota Local Road Research Board, MnDOT, and SRF performed an evaluation of a portable weigh-inmotion (WIM) system at several locations throughout Minnesota. The system was developed at the University of Minnesota-Duluth and offers roadway designers a low-cost method for obtaining vehicle load distribution data across the state's road network. To deploy the system, the weigh pads of the system were temporarily affixed sensors across the roadway lanes. As vehicles passed over the weigh pads, pressure sensors within the pads detected the weight of vehicles and the system recorded the data for later analysis. Traditional methods for travel monitoring generate traffic volume and classification data, but weigh-in-motion systems give designers a more accurate idea of current and projected traffic loading demands. SRF's testing provided implementation refinements that were incorporated into the system. During the two-year deployment process, the portable WIM system was installed under a wide array of environmental conditions to demonstrate the system's capabilities. Data generated by the system was analyzed. The Final Report details system deployment, calibration, and system accuracy.