In the Missoula Air Stagnation Zone most new roads, parking lots and residential driveways must be paved. You can use the wood stove Air Stagnation Zone map linked to below to see if specific property is inside or outside the Missoula Air Stagnation Zone.
The Missoula Air Stagnation Zone has paving rules for new driveways, parking lots and roads because road dust used to cause violation of the particulate National Ambient Air Quality Standard. By paving existing gravel roads, switching to deicer in place of sand for winter traction, and requiring new vehicle use areas to be paved, Missoula has been able to meet and maintain compliance with the particulate standard.
By definition, a residential driveway serves 2 or fewer residential units. A new duplex access would count as a new driveway and and an access for a new tri-plex would count as road. New driveways that access a paved road must be paved 20 feet back from the paved road or to the edge of the right of way, which ever is longer.
If a new driveway accesses a gravel road the driveway may not be required to pave but a waiver of the option to protest a road paving SID/RSID will need to be completed and filed at the Missoula County Clerk and Treasurers Office. See driveway application and waiver form below.
Parking Areas and Road
Most new roads and parking lots in the Missoula Air Stagnation Zone must be paved. Storage yards may not be required to pave, but minimal gravel standards and emissions controls would then be required. See application and permit link below.