Passing on a multi-lane highway
Passing on a multi-lane highway is a routine maneuver, but it depends on consistent lane discipline, sustained visibility, and a clear judgment of closing speed. The basic rule is that you pass on the left, return only when the vehicle you overtook is fully visible in the inside mirror, and maintain a following distance that leaves room for braking if another driver changes lanes. Conditions such as road markings, truck blind spots, merge traffic, and limited sight distance can change whether a gap is truly safe.
Essential answer
When passing on a multi-lane highway, the key is to use the left lane for the overtaking movement and avoid passing on the right unless traffic is moving in clearly separated lanes at different speeds. Before changing lanes, check the rearview and side mirrors, glance at the blind spot, and signal early enough that other drivers can react. A safe pass means you are not forcing another vehicle to brake or steer to avoid you.
The maneuver is not finished when your front bumper clears the other vehicle. Continue at a steady or slightly higher speed until the passed vehicle appears fully in the interior mirror, then signal and move back without cutting in. In heavy traffic, reset your following distance before considering another pass, because a driver ahead may brake for slowing traffic while you are still committed to the left lane.