M-46 is an east–west state trunkline highway in the US state of Michigan between Muskegon and Port Sanilac, terminating near Lake Michigan and Lake Huron on each end. Except for the north–south segment that corresponds with the US Highway 131 (US 131) freeway between Cedar Springs and Howard City, M-46 is practically a due east–west surface highway. The road runs through rural sections of the Lower Peninsula connecting several freeways including US 31, US 131, US 127 and Interstate 75 (I-75). The highway was formed by July 1, 1919, along two discontinuous sections of its current corridor. The gap was filled in by 1927, but a second break in the routing was created in the 1930s. This second interruption in the corridor was eliminated within a year. The various paths that M-46 has followed have been straightened over the intervening years, producing the modern corridor by the 1970s. Other changes have been made to the location of the western terminus in Muskegon, but it has remained fixed in its current location since 1984. Route description M-46 is one of three trans-peninsular highways in the Lower Peninsula, starting blocks away from Lake Michigan in Muskegon and running almost to Lake Huron in Port Sanilac. The other two highways that do this are M-55 (Manistee – Tawas City) and M-72 (Empire–Harrisville). The highway is maintained by the Michigan Department of Transportation (MDOT) like all other state trunkline highways in the state. The department tracks the traffic volumes along all state highway highways as a part of its maintenance responsibilities using a metric called average annual daily traffic (AADT). This measurement is a calculation of the traffic level along a segment of roadway for any average day of the year. In 2009, MDOT figured that lowest traffic levels were the 1,855 vehicles used the highway daily near the eastern terminus. The peak traffic volumes were the 30,505 vehicles AADT along the section of M-46 immediately east of the US 31 freeway near Muskegon. The trunkline has been listed on the National Highway System (NHS) between the western terminus and US 31, and between Cedar Springs and the M-53 junction in Sanilac County. The NHS is a network of roadways important to the nation's economy, defense, and mobility. Muskegon to Saginaw M-46 starts at an intersection between Muskegon and Apple avenues near the downtown Muskegon business district. The highway follows Apple Avenue eastward through