Measurements of Pavement Condition and Road Weather Environment Within North Dakota Using a Tow-Hitch Mount Road Grip Tester

Each year, hundreds of accidents nationwide are reported that are attributable to a loss of vehicular traction. Many of these accidents are associated with snow and ice accumulation on roadways as a consequence of winter storms or by the formation of pavement frost or black ice during more quiescent weather regimes. A cooperative effort between the University of North Dakota, the Ohio Department of Transportation, Halliday Technologies, Inc., the Rural Geospatial Innovations program, and the Aurora Program was undertaken to collect data on road surface friction conditions utilizing a test research vehicle equipped with a tow-hitch mount road-grip test unit. The unit is mounted at an offset angle to the alignment of the remainder of the wheels on the research vehicle, thereby producing a net sideways drag force that varies with the amount of grip, which is a function of the pavement condition. A software console inside the vehicle provided road grip values at a 1 Hz frequency. Winter 2006–2007 measurements with the research vehicle involved two different measurement methodologies. This paper reports on real-time measurements on eastern North Dakota primary routes during winter weather events, utilizing an onboard Global Positioning System (GPS)–encoded video system for precise tracking and high-resolution visual characterization of the roadway environment. Also briefly discussed is a data fusion effort to utilize the road grip data, the GPS-encoded video, and onboard measurements of pavement and air temperature to obtain a more complete depiction of the wintertime road weather environment.