Can I linger in the left lane in Idaho, speed up if someone is passing me? Here’s the law.

BOISE (Idaho Statesman) — Passing someone with your car on the roadway seems a simple enough task, but the laws surrounding overtaking may be more nuanced than you think.

Two readers recently wrote in with specific questions about overtaking laws:

Is driving on the inside/left lane illegal if you’re not passing?

Is it illegal to speed up when someone tries to pass you? Here are the Idaho laws for both questions.

IDAHO LAW ON LANE ROLES

In Idaho, drivers are instructed to stay in the right lane except to pass in most situations. On roads with three or more lanes in the same direction, the center lane is optimal if there is a lot of entering or exiting traffic.

The Idaho Statutes state the exact scenarios in which a driver is not expected to keep right:

• When overtaking another vehicle proceeding in the same direction
• When an obstruction makes it necessary to drive on the left side of the highway
• Upon a highway divided into three marked lanes
• On a highway restricted to one-way traffic

Additionally, drivers going faster than the traffic flow on roadways with more than two lanes in the same direction are not required to remain in the right-hand lane exclusively. However, remaining in the left-hand lane for too long can be considered a traffic violation if it impedes traffic flow, so the center lane is recommended.

Vehicles traveling at less than the normal speed of traffic are also expected to drive in the right lane or as close to the right-hand curb as possible unless overtaking or preparing to turn left at an intersection.

The law states that drivers should only pass when safe and return to the right-hand lane as soon as possible. It is generally recommended to pass only one car at a time.

CAN SOMEONE SPEED UP IF I’M TRYING TO PASS LEGALLY?

Another reader asked about speeding up while passing and whether accelerating in the outside lane is legal when another vehicle attempts to pass you in the inside lane. It’s a common occurrence that has likely happened to everyone at least once.

But is it illegal? Based on the Idaho Statutes, it would be considered dangerous driving.

Title 49, Chapter 6 of the Statutes states that the driver of an overtaken vehicle is required to give way to the overtaking vehicle. Notably, the statute explicitly notes that a car “shall not increase the speed of his vehicle until completely passed by the overtaking vehicle.”