When there are three or more lanes going in one direction on a highway, which lane should fast-moving vehicles use?

Fast-moving vehicles should use the left lane when there are three or more lanes going in one direction on a highway. This guideline is based on the principle that the leftmost lane is typically designated for passing or for vehicles traveling at higher speeds. It is essential for maintaining an efficient flow of traffic, as it allows slower vehicles to remain in the right lanes and prevents congestion.

Using the left lane for fast-moving vehicles also enhances safety by reducing the need for frequent lane changes. Vehicles traveling at slower speeds should generally stick to the right lanes to allow faster traffic to pass on the left, helping to minimize disruptions and potential accidents.

The other lanes serve specific purposes where slower vehicles should remain, which contributes to overall traffic harmony and safety on multi-lane highways.