When a passing lane opens up and a truck is traveling slowly, what should the truck driver do?

The truck driver should go into the right lane and allow the cars to pass on the left because this action maximizes safety and efficiency on the road. When the passing lane opens up, it indicates that other vehicles may want to overtake slower vehicles, such as trucks. By moving to the right lane, the truck driver enables faster-moving cars to safely maneuver around the truck on the left without causing potential collisions.

This practice aligns with the rules of the road that encourage slower vehicles to maintain positions that allow for smoother traffic flow. By staying in the left lane, the truck could impede the progress of following vehicles, causing frustration and potentially unsafe passing maneuvers. Moving to the right thus creates a safer environment for all road users.