You may not cross a single broken white or yellow line:
- When doing so would interfere with traffic. ✓
- When turning left into a driveway.
- When the car in front of you is disabled.
- When passing to the right on a one-way street.
Answer: A. When doing so would interfere with traffic.
You may not cross a single broken white or yellow line when doing so would interfere with traffic.
Why this is the answer
The manual says a single broken line lets you pass or change lanes only when you can do it safely and without getting in the way of other traffic. So the line itself does not forbid crossing; it sets a condition. If crossing would interfere with traffic, that condition fails and you may not cross. The color tells you whether the traffic beside you moves the same way (white) or the opposite way (yellow), but the safety condition is the same.
Why the other answers are wrong
- B. When turning left into a driveway. — A left turn into a driveway is an exception mentioned for a solid line on your side of a solid-and-broken pair, not a general bar to crossing a single broken line.
- C. When the car in front of you is disabled. — The passages do not make a disabled car ahead a reason you cannot cross; a broken line still allows the move when it is safe and does not interfere.
- D. When passing to the right on a one-way street. — Passing to the right on a one-way street is not addressed as a bar in the passages; with a broken line the test is whether the move is safe and does not interfere with traffic.
Remember it
Think of a broken line as "yes, if clear" — the moment your move would block someone, it turns into "no."