Practice question

Which technique helps you check for a vehicle in your blind spots before changing lanes?

  1. Rely on mirrors only.
  2. Turn the steering wheel in the opposite direction.
  3. Look over your shoulder after you have already moved.
  4. Use rearview and side mirrors and quickly glance over your shoulder in the direction you plan to move.

Answer: D — Use rearview and side mirrors and quickly glance over your shoulder in the direction you plan to move.

Before you change lanes, you need to actively check for vehicles in your blind spots by using your mirrors and adding a quick over-your-shoulder glance toward the lane you plan to enter. Mirrors show what’s behind and to the sides, but blind spots exist where they can’t see—so a short head turn helps confirm the lane is clear before you move. Relying on mirrors alone leaves those blind spots unchecked, and turning the steering wheel the other way doesn’t provide visibility into adjacent lanes. Looking over your shoulder after you’ve already started to move is unsafe because you could collide with a vehicle you didn’t see. Using both mirror checks and a quick shoulder check gives you a safer, more complete view before changing lanes.

Practice more: Online California DMV Traffic School Practice Test →