When is it illegal to drive in the left lane on a highway?

Driving in the left lane on a highway is designed primarily for passing slower vehicles or for faster-moving traffic. Therefore, it is considered illegal to drive in the left lane when you are not actively passing another vehicle. This rule helps maintain smooth traffic flow and reduces congestion, as the left lane is intended for those who wish to overtake slower vehicles in the right lane.

Being lost may lead to unsafe driving practices, but it doesn't provide a specific legal reason for restriction in lane use. Rush hour conditions can affect traffic patterns, but they do not change the legality of lane use in terms of passing. Lastly, if the left lane is marked for exit only, it implies a specific traffic regulation that must be followed, but it is a different rule than the general prohibition against impeding traffic in the left lane without a purpose.