Montana has a law that requires slower drivers to let backed-up traffic pass.
The rule, in effect since 1959, applies when four or more vehicles are behind you on a two-lane road.
The law is designed to prevent frustrated drivers from attempting dangerous overtakes. According to the Montana Highway Patrol, many motorists are unaware of the regulation.
What the Law Says
Montana Code Annotated 61-8-311 states that if you are driving significantly slower than traffic and four or more vehicles have lined up behind you, you must use the next safe turnout to let them pass.
This does not mean stopping abruptly or pulling into a ditch; the law references the nearest safe turnout area or a suitable shoulder if conditions permit.
Sergeant Philip Smart of the Montana Highway Patrol told NBC Montana that the rule aims to keep traffic flowing and reduce frustration.
The longer a queue grows, the more likely someone will attempt a risky passing maneuver on winding rural highways.
For those learning about the rule for the first time, Smart noted that most encounters are educational rather than punitive.
“I understand that people are probably not super familiar with this rule,” he said.
Montana is not the only state with such laws, but the four-car threshold makes its approach unusually specific.
Drivers heading to Montana lakes with campers, boats, or overloaded SUVs are advised to check their mirrors.
