(1) operates any of the vehicles described below & doesn't drive in the right lane of all roadways having 2+ lanes for traffic proceeding in a single direction.

(a) any camper

(b) any trailer

(c) any vehicle with a registration weight of 10,000 lbs or more

(2) exceptions:

(a) when overtaking & passing another vehicle going in the same direction when the movement can be made without interfering with the passage of other vehicles & per:

• 811.410 (unsafe passing on the left)

• 811.415 (unsafe passing on the right)

• 811.420 (passing in a no passing zone)

• 811.425 (failure of slower driver to yield to overtaking vehicle)

(b) when preparing to turn left.

(c) when reasonably necessary in response to emergency conditions.

(d) to avoid actual or potential traffic moving onto the right lane from an acceleration or merging lane.

(e) when necessary to follow traffic control devices that direct use of a lane other than the right lane.