Tennessee drivers can no longer cruise in the fast lane while on the interstate. The state's new "slow poke law" took effect Friday and officers are enforcing it. Tennessee Highway Patrol says the law could help ease traffic backups and improve safety.

The law prohibits the operation of vehicles in a passing lane on interstates or multi lane highways except when passing.

There are exceptions to the slow poke law. The slow poke law will not apply if inclement weather or an official traffic control device makes it necessary to drive in the passing lane, if there are obstructions in the non-passing lanes or if highway design makes it necessary to drive in the passing lane to exit or turn left.