 As the highway is still under state jurisdiction, M-155 is maintained by the Michigan Department of Transportation (MDOT).In 2011, the department's traffic surveys showed that on average, 13,699 vehicles used the highway daily in Howell and 3,960 vehicles did so each day near the southern terminus, the highest and lowest counts along the highway, respectively.No section of OLD M-155 is listed on the National Highway System, a network of roads important to the country's economy, defense, and mobility.