Road Signs, Signals, and Markings
Reading the road's language
Signs fall into three families: regulatory (red/white or black/white, they command - STOP, YIELD, speed limit, no entry), warning (yellow diamond or pentagon, they advise - curves, pedestrian crossings, school zones), and guide/informational (green, blue, or brown, they orient - destinations, services, recreation). Shape carries meaning independent of words: an inverted triangle means yield, an octagon means stop, a pennant marks a no-passing zone, a round sign warns of a railroad crossing ahead, and a crossbuck marks the crossing itself.
Signals override signs, and a police officer's directions override signals. A steady red means stop; a steady yellow means the light is about to turn red and you should stop if you can do so safely; a steady green means proceed when clear. Flashing red behaves like a stop sign; flashing yellow means proceed with caution. A green arrow protects your turn - oncoming traffic is stopped - but a green circle does not.
Pavement markings reinforce the same rules. Yellow lines separate traffic moving in opposite directions; white lines separate traffic moving the same way. A broken line may be crossed when safe; a solid line should not be. A double solid yellow line forbids passing in both directions.
Trap: questions often show a yellow light and ask whether you must stop. The answer is "stop if safe," not "always" and not "never." Another common trap is confusing a warning sign's yellow diamond with a regulatory sign's yellow background on a pedestrian or school sign.
Rule of thumb: classify the sign by color and shape first, then read the words - this resolves most ambiguous items in seconds.