Is it legal to speed when passing another vehicle? Here’s the new law in Idaho

Idaho drivers are now permitted to temporarily exceed the posted speed limit by up to 15 mph so they can pass a vehicle driving below the limit on roads with a minimum speed limit of 55 mph outside of city limits.

Previously, Idaho law allowed exceeding the speed limit only on two-lane undivided highways during a passing maneuver.

“A little frustrated at the lack of that enforcement at passing lanes, because they are not utilized correctly, and that creates more road rage and more unsafe conditions than probably any other thing going up Highway 55 and 95,” said state Rep. Charlie Shepherd, who proposed changing the law, during the 2025 legislative session. Shepherd lives in Pollock, a hamlet along U.S. 95 in Idaho County south of Riggins, a highway he travels through winding, mountainous country when he commutes to Boise for legislative business.

The Legislature updated the statute to include passing lanes effectiveJuly 1. Some of the rules attached, according to state law, include:

• The person you’re passing must be driving under the speed limit.
• You must pass on the left. You cannot pass on the right.
• The new permission does not apply if you are driving a truck or tractor-trailer or are towing an item. You must be driving a car, pickup or motorcycle.
• The new permission does not apply within city limits or in sections of the highway that are 55 mph or below.

The Idaho Department of Transportation reminded drivers in an Instagram post to move over when a vehicle is parked on the shoulder of the road and to move over for all emergency vehicles with flashing lights, including critical-incident response vehicles and tow trucks.

This story was originally published July 7, 2025 at 4:00 AM.