Keep right except to pass.
It's the law.
But Washington State Patrol says too many drivers are unaware of the law -- or just don't follow it.
The state is conducting an emphasis patrol starting March 16 to bring increased awareness to the left lane law.
Last year, troopers stopped 13,909 left lane law violators.
Multiple states are taking aim at drivers clogging up the left lane on highways by passing laws that could lead to fines up to $500 for drivers who refuse to move over when traffic backs up behind them.
Studies have continuously shown it is safer to pass on the left. Drivers hogging the left lane also increase the likelihood of crashes by backing up traffic.
Forty states now have some form of penalty in place for drivers clogging up traffic, according to CNBC.