Iowa Road Signs Practice cheat sheet

Octagon (eight sides) is reserved exclusively for STOP; no other sign uses this shape, so an octagon is identifiable by silhouette alone.

Inverted triangle (apex down) means YIELD; it is the only downward-pointing triangle in the U.S. sign system.

Horizontal rectangle with longer side horizontal generally carries regulatory word messages (speed limit, lane use, turning restrictions).

Vertical rectangle (longer side vertical) typically carries warning messages or destination/directional information.

Diamond (rotated square) marks a warning or caution condition ahead; yellow diamonds warn of general hazards, orange diamonds mark construction and maintenance zones.

Pennant (isosceles triangle pointing right) marks a No-Passing Zone; it is placed on the left side of the roadway in the direction of travel.

Round signs mark railroad advance warnings (yellow circle with X and RR) and, in some applications, highway route markers.

Red means stop, yield, or prohibited action; white background with black legend is regulatory; yellow is warning; orange is construction; green is guidance/destination; blue is services; brown is recreation and cultural interest.

Fluorescent yellow-green is used for pedestrian, bicycle, and school warning signs, distinguishing those warnings from ordinary yellow hazard warnings.

A sign legend is read top to bottom; on multi-line regulatory signs the top line states the condition and the bottom line states the required action.

Speed limit signs are regulatory: the posted number is the legal maximum in ideal conditions, not a recommended speed, and lower speeds are required when conditions warrant.

Warning signs are placed in advance of the condition; the distance to the hazard is not uniform, so slow down on seeing the sign rather than at the hazard.

A yellow diamond with a black arrow or curve symbol indicates the direction of the upcoming curve; the arrow shape matches the actual road geometry.

Crossbuck (X-shaped) signs with the words RAILROAD CROSSING mark the crossing itself; yellow round advance-warning signs appear before it, and pavement markings supplement both.

Five-sided (pentagon) signs mark school zones and school crossings; the sign shape is unique to school-related warnings.

A red circle with a diagonal slash means the depicted action is prohibited; a red slash without a circle means the action ends or is no longer permitted.

Construction and work-zone signs are orange; a flagger symbol or worker symbol warns of people in or near the traveled way, requiring reduced speed.

Pavement markings work with signs: a solid yellow line on your side of the center line means no passing, and a broken yellow line means passing is permitted when safe.