Large trucks cruising down some Tennessee highways will soon be prohibited from driving in the far left lanes.

The new rule, approved this spring by state lawmakers and Gov. Phil Bredesen, took effect late last month, but cannot be enforced until signs are posted along about 235 miles of affected interstate.

“We couldn’t post signs until the law took effect, and the law can’t be enforced until the signs are up,” Department of Transportation Spokeswoman Kim Keelor told The Tennessean. She estimated that all signage should be in place by year's end.

Under the new law, truckers driving through Tennessee are restricted to the right hand lanes on interstates with three or more lanes of traffic in each direction. Violators would face up to a $50 fine.

Exceptions will apply in instances where signs are not plainly visible or installed; in construction zones; when trucks are passing slower vehicles; and spacing between trucks in traffic is less than 500 feet per lane.

The Owner-Operator Independent Drivers Association opposes lane restrictions for any class of vehicle.

“Such restrictions invariably cause more problems than they fix,” said OOIDA Executive Vice President Todd Spencer.

“Trucks and other vehicles need to be able to move over a lane when necessary. It’s common courtesy, but this is also about highway safety.

“When you start restricting vehicles to certain lanes, you end up with more vehicles tailgating and making unsafe passing maneuvers in all lanes. This isn’t good for congestion or highway safety.

“Lane restrictions that discourage smart, safe driving practices are just absurd.”