Speed limits are posted to protect the public by informing drivers of the authorized, allowable speed. Common speed limits are typically statutory as stated in Montana Code Annotated 61-8-303. Speed restrictions.
Daytime speed limits are in effect from one-half hour before sunrise to one-half hour after sunset. Nighttime speed limits are in effect at any other time.
The speed limits in Table 1 went into effect October 1, 2019. These speed limits apply unless otherwise posted.
|Type of Highway||Cars and Light Trucks||Heavy Trucks*|
|Interstate Within Urban Area **||65||65||65||65|
* over one ton manufacturer's rated capacity
** Billings, Great Falls and Missoula