Open in: [Superset)] [ArcGIS] or [Request format]Open in: [Superset)] or [Request format]The Act51 Map Layer represents the road network that the City of Detroit reports to the Michigan Department of Transportation on a annual basis. The Act51 Map Layer identifies road jurisdictions for permitting and planning.Public Act 51 of 1951 created the Michigan Transportation Fund (MTF), and it is the main road funding source for most cities and villages. This Act defines the formula by which Michigan distributes money for road maintenance to cities, villages, and counties.Under Act 51, county roads can be classified as either primary or local roads. City and village streets can be classified as either major or local streets. Primary roads and major streets are selected by the counties, cities and villages on the basis of the greatest general importance to each respective local agency.