Montana raises truck speed limit to 70 mph on interstates

May 15, 2019

Tyson Fisher


Montana is the most recent state to act this year to make speed-limit changes. Gov. Steve Bullock has signed into law a bill to raise truck speed limits.

Previously HB393, the new law will raise the speed limit for trucks on interstate highways from 65 mph to 70 mph throughout the day. Truck speed limits on all noninterstate highways will be set at 65 mph for all hours of the day.

State highways now are limited to 60 mph during the day and 55 mph at night. Cars are allowed to travel 65 mph on noninterstate highways and up to 80 mph on rural interstate highways.

“Speed limits should be set to keep traffic flowing freely. Currently trucks are set at 10 mph below the rest of traffic, which causes congestion on our highways,” Rep. Joshua Kassmier, R-Fort Benton, testified during a recent hearing. “It is my belief that allowing traffic to flow more freely is in the best interest of everyone’s safety.”


The Owner-Operator Independent Drivers Association says roadways are safest when all vehicles are allowed to travel at the same rate of speed. The Association does not advocate for a specific speed limit.

“Our members are opposed to differential speed limits because they are counterproductive to safety, limit the ability of truck drivers to fully control their vehicles, and negatively impact the behavior of other drivers and vehicles,” Matousek communicated to Kassmier.

“Ultimately, they create more interactions between cars and trucks, which leads to dangerous passing, aggressive driving, and an increase in the number of accidents.”

Matousek adds that different passenger vehicle and truck speed limits are also a contributing factor to increased congestion and inefficiencies with local, regional, and national goods movement.

Action elsewhere

Legislators around the nation have taken action this year to boost speed limits for all vehicles or – as in the case of Arkansas – to enact speed limit differentials for cars and trucks.


One new law is intended to speed up conversion to higher speed limits on certain highways around the state. A change will also reintroduce a speed differential in the state.

A 2-year old Arkansas law permits the State Highway Commission to increase speed limits only after completing an engineering and traffic investigation. The maximum speed limits on controlled-access highways can be 75 mph.

This year’s revision to statute mandates a 75 mph speed limit on freeways outside urban areas. The large truck speed limit, however, will be set at 70 mph.

Speed limits on urban freeways will be set at 65 mph for all vehicles.

The changes are scheduled to take effect in July 2020.

The new rule states that a stretch of roadway would revert to its previous maximum only after an engineering and traffic investigation that finds the new maximum is unsafe.


A new law adds Interstate 165 to the list of highways and parkways in the state with 70 mph speed limits posted. Faster travel for all vehicles is also authorized for the entire length of the highway.

In addition, 70 mph travel is allowed for the entire length of the Bert T. Combs Mountain Parkway Extension. Currently, 70 mph travel is allowed along the parkway from I-64 to the beginning of the Mountain Parkway Extension in Wolfe County. Elsewhere on the affected parkway, a 65 mph speed limit is posted.


One new law amends rules on speed limits for the state’s turnpike system and interstate highways.

Oklahoma already permits all vehicles to travel at 75 mph on four-lane divided highways, including interstates. A 2016 state law, however, permits higher posted speeds after a state Department of Transportation engineering and traffic investigation.

The rule change authorizes the speed limit on the turnpike system to be raised to 80 mph – up from 75. The new law also permits the maximum posted speed on rural interstate highways to be increased from 70 to 75 mph.

West Virginia

The Legislature approved a resolution that could result in a change to the posted speed on the state’s fastest highways.

House Concurrent Resolution 32 gives the state DOT authority to increase the speed limit on interstate highways from 70 mph to 75 mph. Specifically, the measure grants the agency authority to make changes “where appropriate” on interstates.

Pilot Flying J
Tyson Fisher

Tyson Fisher joined Land Line Magazine in March 2014. An award-winning journalist and tireless researcher, his news reports, features and blogs bring depth to our editorial content, backed with solid detail. Tyson is a lifelong Kansas Citian.