Which of the following is not a safe driving practice when driving on the interstate?
- Slower traffic must keep to the right.
- Change lanes without signaling. ✓
- If you miss your exit, you must go to the next exit.
Answer: B. Change lanes without signaling.
Changing lanes without signaling is the unsafe practice; you should always signal before you move over.
Why this is the answer
The handbook's lane-change steps start with signal, then check mirrors, check traffic behind and beside you, and look over your shoulder into the blind spot for other vehicles, motorcyclists, and bicyclists. It also warns that last-minute lane or direction changes raise the risk of a collision. Moving into another lane without letting anyone know you are coming breaks the first step of that sequence, so other drivers get no warning of where your car is about to go.
Why the other answers are wrong
- A. Slower traffic must keep to the right. — Keeping slower traffic to the right is a safe habit, not an unsafe one, so it does not answer what is not a safe practice.
- C. If you miss your exit, you must go to the next exit. — Going on to the next exit is safe: the handbook says if you miss a turn, keep driving until you can safely and legally turn around, so this is not the unsafe choice.
Remember it
Signal first, then mirrors, then the shoulder check — if the signal is skipped, the whole lane change starts wrong.
Official handbook: California Driver Handbook (DL 600), Section 6: Navigating the Roads, p. 15