When are you allowed to drive in the left lane of a highway?

Driving in the left lane of a highway is primarily reserved for passing other vehicles. This practice helps maintain a smooth traffic flow and encourages faster vehicles to move past slower-moving traffic. The left lane is often referred to as the "passing lane," and using it appropriately helps reduce congestion and enhances safety on the roadway.

When you are passing another vehicle, it's crucial to ensure that it is safe to do so, including checking mirrors and blind spots, signaling your intention, and adhering to speed limits while executing the maneuver. After completing the pass, it's advisable to return to the right lane to allow others to use the left lane for passing as well.

The other choices do not align with the primary rule regarding the use of the left lane. For instance, driving in the left lane due to a closed right lane may be permissible but is not a standard rule. Heavy traffic does not justify occupying the left lane if you're not actively passing, and driving over the speed limit is not permissible regardless of lane choice. Therefore, using the left lane appropriately while passing supports safe and efficient highway travel.