Every sign on the Colorado test.
Organized by category and color. The federal MUTCD standard, the same set every state's knowledge test draws from.
Road signs follow a federal standard (MUTCD), so the same shape and color mean the same thing in every state. Color tells you the category: red for prohibitions, yellow for warnings, orange for work zones, green for guides, blue for services, brown for recreation, yellow-green for school and pedestrian zones. Shape tells you the function: an octagon is always a stop, a triangle pointed down is always a yield, a diamond is always a warning. Once you read the system, every sign falls into place.
Regulatory Signs
Warning Signs
Work Zone Signs
Recreation and Cultural Signs
Guide Signs
School and Pedestrian Signs
Railroad Crossing Signs
Route Markers
The full-color road signs cheat sheet, free.
The shape and color system plus the core signs to know cold, in a printable full-color PDF. Print it and keep it with your study materials.