When changing lanes:
- Rely on the rearview mirror.
- Look over your shoulder in the direction you plan to move. ✓
- Rely on the left side mirror.
Answer: B. Look over your shoulder in the direction you plan to move.
When changing lanes, look over your shoulder in the direction you plan to move.
Why this is the answer
The California handbook lists the steps before a lane change: signal, check your mirrors, check traffic behind and beside you, and look over your shoulder toward the lane you plan to enter to make sure it is clear. It also says to check blind spots for other vehicles, motorcyclists, and bicyclists. Mirrors are part of the check, but the handbook specifically calls for the shoulder look before moving into another lane.
Why the other answers are wrong
- A. Rely on the rearview mirror. — Relying on the rearview mirror is not enough because the handbook's lane-change steps include checking mirrors along with checking traffic behind and beside you and looking over your shoulder.
- C. Rely on the left side mirror. — Relying on the left side mirror is not enough because the handbook calls for a shoulder check in the direction you plan to move, plus checking blind spots, not just one mirror.
Remember it
Before you move, turn your head toward the lane you want; that shoulder check is the step mirrors alone do not cover.
Official handbook: California Driver Handbook (DL 600), Section 6: Navigating the Roads, p. 15