When changing lanes on a highway, you should:
- Signal a lane change.
- Check your rearview and outside mirrors.
- Check your blind spot by glancing over your shoulder.
- All of the above. ✓
Answer: D. All of the above.
When changing lanes on a highway, you should signal, check your rearview and outside mirrors, and glance over your shoulder to check your blind spot — all of the above.
Why this is the answer
The handbook says to turn your head before moving to change lanes on a highway so you can check the blind spots near the rear corners, which your rear-view mirrors and peripheral vision do not cover. It also says to activate your signal before moving into the left lane so other drivers know your plan. Checking the mirrors before the shoulder glance fits the same sequence, since the handbook treats mirrors as one view and blind spots as what they miss. Each action covers a different part of the check, so the choice listing all of them is correct.
Why the other answers are wrong
- A. Signal a lane change. — Signaling alone tells others what you plan to do, but it does not confirm that the space is clear, so it is only one part of the maneuver.
- B. Check your rearview and outside mirrors. — Looking in the rearview and outside mirrors helps, but the handbook defines blind spots as areas those mirrors do not show.
- C. Check your blind spot by glancing over your shoulder. — Glancing over your shoulder covers the blind spot, but by itself it does not announce your move or give you the mirror view.
Remember it
Signal first, mirrors second, shoulder last — then move only when all three say clear.