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 do all of these: signal the lane change, check your rearview and outside mirrors, and glance over your shoulder to check your blind spot.
Why this is the answer
The handbook's lane-change and passing steps put these checks together: you look in the rearview mirror, the side mirrors, and over your shoulder into the blind spot to confirm the roadway is clear and nobody is passing you, then you turn on your signal to warn drivers behind you. Because each action is part of the same safe lane change, no single one of them alone is the answer. The motorcycle section repeats the same idea, telling drivers to check mirrors and blind spots before entering or leaving a lane.
Why the other answers are wrong
- A. Signal a lane change. — Signaling alone tells drivers behind what you plan to do, but it does not confirm the lane is actually clear.
- B. Check your rearview and outside mirrors. — Mirror checks leave the blind spot uncovered, where a smaller vehicle can be hidden from your mirrors.
- C. Check your blind spot by glancing over your shoulder. — A shoulder glance covers the blind spot but skips the mirror checks and the signal that warns traffic behind you.
Remember it
Think of a lane change as three moves in order: signal, mirrors, then a quick look over your shoulder before you move.