DC Road Signs: Color, Shape, and Required Action
Road signs is the domain that tests sign recognition by color, shape, and symbol, plus the action each sign requires. DC exam questions often describe a sign rather than show it, so learn the system: red means stop or prohibit, yellow warns, orange marks work zones, white regulates, green guides, blue provides services, and brown marks recreation.
Shape and color cues
An octagon is always STOP. A downward triangle is YIELD. A diamond warns of a hazard ahead. A pentagon marks a school zone or school crossing. A round yellow sign warns of a railroad crossing ahead; the crossbuck marks the crossing itself. A red circle with a slash means the action is prohibited.
Regulatory versus warning
White signs with black or red text are regulatory: they give orders such as speed limits, lane use, parking rules, or turn restrictions. Yellow signs are warnings: curve, hill, merge, pedestrian, or signal ahead. They do not change the legal speed limit unless a separate regulatory sign does. Orange signs are temporary work-zone controls. In DC, photo-enforcement signs may appear near speed or red-light cameras; treat them as information, not permission to ignore the rule.
Worked example
A question describes a yellow diamond with a black truck symbol on a downhill slope. What does it mean? The color and diamond shape identify a warning; the truck on a slope warns of a steep downgrade. The correct action is to slow down and use a lower gear so you do not ride the brakes. It is not a truck-route sign and it does not set a 25 mph limit; the symbol warns of the hazard.
Traps that cost marks
Do not treat every yellow sign as a speed limit. Do not read a white regulatory sign as a warning. Do not assume a yield sign requires a full stop when the way is clear, but do be ready to stop. Do not ignore an orange work-zone sign because no workers are visible. Do not confuse a no-parking sign with a no-stopping sign; stopping is more restrictive.