Each year the Montana Department of Transportation (MDT) is required to determine fuel tax allocations distributed to Montana's cities, counties, and consolidated city-county governments set forth in 15-70-101 MCA, as amended.
One of the factors used to calculate the amount allocated to each local entity is road mileage. Mileages for counties consist of any road exclusive of the National Highway and Primary Systems within the county boundary and outside any incorporated city limits that meet the criteria of "open to public travel" as stated below:
Open to Public Travel is defined as a segment of road available for public use except during periods of extreme weather or emergency conditions, passable by a 2-wheel drive passenger car and open to the general public. Restrictions include; primitive trails, driveway to a single residence, field access roads, parking lots, restrictive gates, orange markings on posts, or "No Trespassing" signs (MCA 45-6-201).
MDT conducts field inventories yearly while working with local governments to collect new route centerlines using GPS technology to ensure the routes are "Open to Public Travel".
These routes meet “Open to public travel” requirements to be used for Fuel Tax Allocations and do not indicate public access, ownership or maintenance responsibility. Maintenance is not a factor in Fuel Tax Allocations nor are the local governments required to maintain these routes. The mileage of these routes is one factor used to determine the percentage of the overall allocations that the local government will receive according to 15-70-101 MCA.
Our database is continuously updated. In addition to the annual mileage certification returns from the cities and counties, results from field reviews and the discovery of errors can have an effect on the mileage numbers from year to year.
Official fuel tax roads, mileages and maps are held in the office of MDT. For requests or comments please
Effective July 1, 2017, HB473, the Bridge and Road Safety and Accountability Act increases Montana's fuel tax rates and allows for additional allocations to the local governments. These additional allocations will be handled separately from the existing allocations described in this document. If you have questions about the new allocations you can contact Geoff Streeter at 406-444-9131 or via
Visit the Road & Bridge Funding in Montana web page.