BOISE, IDAHO — Idaho Governor Brad Little signed House Bill 664 into law on Monday, March 23, 2026. Starting July 1, semi trucks and passenger vehicles will share the same 80 mph speed limit on Idaho interstates. The separate lower limit for commercial trucks is gone.
Supporters pushed the bill on safety grounds. Research cited in the legislation found that a 10 mph speed difference between vehicles increases dangerous highway interactions by as much as 227%. The argument: speed differential, not speed itself, creates the real danger.
What Truck Drivers Are Saying
Arvel, a long-haul trucker who logs more than 3,000 miles a week on a route from Ohio to Idaho, told Idaho News 6 the change will smooth out traffic flow. He described the current dynamic on Idaho interstates.
“I’m doing 70, he’s doing 65 — I go to get over — and this car is coming up probably doing 80, 85 mph. Now, they’re hopping in the right lane to go around you because they think you cut them off,” Arvel said. “In the states that I’m driving through that have everybody doing the same speed limit, it’s much smoother.”
Arvel also noted the law won’t affect every truck. Many carriers install engine governors that cap speeds at 65 to 68 mph. Those drivers will stay in the right lane regardless of the posted limit.
“Some of these trucks are governed to about 65 to 68 miles an hour. The guys who are stuck at those governed miles, they pretty much stay in the right lane,” Arvel said. “I don’t believe any of the trucks should be going over 80 miles per hour. I feel like 80 should be the cap.”
What Everyday Drivers Are Saying
Not everyone is on board. Idaho drivers pushed back on social media when asked about the change.
“Don’t think it is a good idea! They usually go over the speed limit anyways, but it is very scary when they go that fast,” one person said.
“I really hope they rethink what they are about to do. It will be a dangerous choice to be on the road with a fully loaded trailer doing 80 mph coming up on you from any direction. I’ve been in their blind spot — at 80 you lose big reaction time. I’ll pray for everyone,” another wrote.
A third driver offered a different take. “So now a truck doing 79 is going to be passed by a truck doing 80. The problem with the speed difference is pulling out to pass and camping in the left lane. Keep the trucks in the right lane and enforce their speed limit,” they said.
House Bill 664 takes effect July 1, 2026.
📸 Image(s) used under fair use for news reporting.
