If there are three or more lanes going in the same direction on a highway, the _________ are usually the smoothest, in terms of the flow of traffic.

Explanation

Smooth driving allows you to keep more distance between yourself and other drivers. It also helps save gas. During ordinary driving, drive in the lane that has the smoothest flow of traffic. If there are three or more lanes going in one direction, the middle lane, or lanes, are usually the smoothest.