Slow drivers in the left lane of the highway would have to move over to the right under a measure passed overwhelmingly by the Florida House of Representatives on Tuesday.
Sponsors say it will help avoid road rage and dangerous situations where frustrated drivers are stuck behind a slow person try to pass on the right.
The bill passed the House 109 to 4 and now goes to the Senate.
Opponents say it will encourage speeding and punish people who drive the speed limit.
The bill says that anyone driving on a four-lane highway can only drive in the left lane when passing another vehicle.