What does a 'slower traffic keep right' sign mean?

The 'slower traffic keep right' sign indicates that drivers who are traveling at a slower speed than the general flow of traffic should stay in the right lane. This is designed to facilitate smoother traffic flow and minimize congestion, particularly on multi-lane roads. By encouraging slower-moving vehicles to occupy the right lane, it allows faster vehicles to pass safely on the left. This rule is important for maintaining safety and efficiency on the road, as it helps prevent situations where faster drivers may have to weave in and out of traffic to overtake slower vehicles.

The other options do not accurately convey the purpose of this sign. For instance, the idea that only trucks must use the right lane is misleading, as it applies to all slower vehicles, not just commercial trucks. Additionally, stating that it applies during rush hour only is incorrect; the rule applies at all times when there is a multi-lane roadway. Finally, the suggestion that drivers should stay in the left lane contradicts the intent of the sign, as it promotes staying right for those traveling at slower speeds.