Final answer:
A slower driver should use the right lane on a highway, which allows faster traffic to pass safely on the left.
Step-by-step explanation:
On a highway, a slower driver should use the right lane or the lane furthest to the right that is available for through traffic. This allows for smoother traffic flow and safer lane management. The left lanes are often reserved for overtaking or faster-moving traffic. Therefore, it is safest for a slower driver to stay in the right lane, not only to conform with traffic laws but also to minimize disruptions in traffic patterns and reduce the risk of accidents.