 As a part of these maintenance responsibilities, the department tracks the volume of traffic that uses the roadways under its jurisdiction.These volumes are expressed using a metric called annual average daily traffic, which is a statistical calculation of the average daily number of vehicles on a segment of roadway.MDOT's surveys in 2010 showed that 986 vehicles in the city of Eaton Rapids, and 1,103 used the trunkline outside of town, traveled along the highway on average.