You must stop at an intersection when you see a:

1. Flashing red light. ✓
2. Steady yellow light.
3. Yellow arrow.
4. Flashing yellow light.

Answer: A. Flashing red light.

You must stop at the intersection when you see a flashing red light.

Why this is the answer

The Texas handbook treats a flashing red light as a full stop: come to a complete stop before the crosswalk or the intersection, then go ahead only when it is safe. It also notes that traffic on the crossing road may not have to stop, so you cannot assume others will yield. A steady yellow is different: it warns that the light is changing and says to stop only if you can do so safely. The other yellow signals do not call for a stop.

Why the other answers are wrong

• B. Steady yellow light. — A steady yellow light is a caution signal; the handbook says to stop before the crosswalk if you can do so safely, and if you cannot, proceed cautiously, so it is not an automatic must-stop.
• C. Yellow arrow. — A yellow arrow, shown as a flashing yellow left-turn arrow, lets you turn left but requires yielding to oncoming traffic, not stopping at the intersection.
• D. Flashing yellow light. — A flashing yellow light tells you to slow down and proceed with caution, not to come to a stop.

Remember it

Red still means stop; the flash just means you may go once you have stopped and the way is safe.