Idaho Road Signs Practice cheat sheet

Regulatory signs tell you what you must do or must not do; they are enforceable and carry the force of law.

White background with black legend and border is the standard color scheme for most regulatory signs (STOP is the major exception).

STOP (R1-1) is a red octagon with white legend; a full stop is required at the stop line, crosswalk, or edge of the roadway.

YIELD (R1-2) is a red-and-white downward-pointing triangle; slow down and give the right-of-way to traffic on the intersecting road.

SPEED LIMIT signs are white rectangles with black legend; the number shown is the maximum lawful speed in ideal conditions, not a recommended speed.

DO NOT ENTER is a red square with a white horizontal bar and white legend; it marks the wrong-way entrance of a one-way road.

WRONG WAY signs reinforce DO NOT ENTER and are posted on the reverse side of freeway ramps facing wrong-way drivers.

ONE WAY signs are black rectangles with white arrows; a white arrow on black indicates the permitted direction of travel.

Movement and turn signs (NO LEFT TURN, NO U-TURN, KEEP RIGHT) are white squares or rectangles with black symbols and a red circle-slash for prohibitions.

Warning signs alert drivers to a change in road conditions ahead; most are yellow diamonds with black legend or symbols.

Warning signs are normally placed in advance of the condition; the distance is not marked on the sign itself, so adjust speed as soon as you see it.

Curve and turn signs show a black arrow; a plaque below may read a recommended speed, which is advisory, not the legal limit.

Winding road, reverse curve, and sharp turn signs each use a distinct arrow shape to describe the alignment ahead.

Intersection warning signs (crossroad, side road, T-intersection, Y-intersection) are yellow diamonds showing the road layout in black.

Merge, lane-ends, and added-lane signs warn of lane configuration changes; the lane that ends is shown narrowing.

Hill, downgrade, and truck-use signs warn of steep grades; a percentage plaque (for example 6%) states the grade.

Advisory plaques are yellow rectangles with black legend mounted below a warning sign; they are not regulatory speed limits.

Object markers and type 3 barricades mark hazards at night and in work zones; they use yellow retroreflective material for added visibility.

Guide signs provide destination, distance, route, and service information; they are informational and are not regulatory.

Green guide signs are used on conventional highways and freeways for destinations, exits, and distances.

Blue signs indicate motorist services such as gas, food, lodging, camping, and hospitals.

Brown signs identify recreational and cultural points of interest, parks, and historic sites.

White guide signs on conventional roads carry route markers, street names, and small destination information.

Interstate route markers use a shield shape; the red top band on an interstate shield carries the word INTERSTATE.

Mileposts and exit numbers give location references; interstate exit numbers generally correspond to mileposts.

A white rectangular sign with black legend reading NEXT SERVICES followed by a distance tells you how far to the next available services.

A steady red light requires a full stop before the stop line or crosswalk; right turns on red are permitted after stopping unless a sign prohibits them.

A flashing red light is treated as a STOP sign: stop, yield, and proceed when clear.

A steady yellow light means the signal is about to turn red; stop if you can do so safely, otherwise clear the intersection.

A flashing yellow light means proceed with caution; it does not require a stop.

A green arrow is a protected movement; traffic turning on the arrow has the right-of-way over opposing traffic.

A solid white line between lanes discourages lane changes; a broken white line permits them when safe.

A double solid yellow line means no passing in either direction; a solid yellow line on your side means no passing from your lane.

Broken yellow lines separate traffic moving in opposite directions and permit passing when safe and legal.

A white stop bar is a thick solid white line marking where vehicles must stop at a signal or stop sign.

Orange is the standard background color for construction and maintenance warning signs.

Work zone warning signs are diamond-shaped orange signs with black legend or symbols.

A flagger symbol sign (orange diamond) warns that a person is directing traffic ahead; obey the flagger's signals.

Channelizing devices include cones, drums, and tubular markers; they guide traffic through or around a work area.

A type 3 barricade has three horizontal rails with alternating orange and white diagonal stripes and marks a road closure or hazard.

Temporary traffic control may include a pilot car, lane shifts, or alternating one-lane operation controlled by flaggers or signals.

Reduced speed limits posted in work zones are regulatory and enforceable when workers are present, even if the sign is temporary.

A ROAD CLOSED or DETOUR sign directs traffic away from the work area; follow the marked detour rather than driving through the closure.

End Road Work signs are orange or black-on-white and mark the termination of a work zone restriction.

The round yellow railroad advance warning sign (crossbuck advance) means a highway-rail crossing is ahead; slow down, look, and listen.

A crossbuck sign (white X with the words RAILROAD CROSSING) marks the crossing itself; yield to trains.

Flashing red lights at a railroad crossing require a stop; do not proceed until the lights stop flashing and the way is clear.

A gate arm lowered across your lane means stop and remain stopped until the gate rises completely.

A number plaque below a crossbuck (for example 2 TRACKS) indicates how many tracks the crossing has; watch for a second train.

School zone signs are fluorescent yellow-green pentagons or diamonds showing pedestrians or children; reduce speed and watch for children.

A SCHOOL SPEED LIMIT sign with a flashing beacon or time plaque sets a lower limit during posted hours or when the beacon flashes.

School crossing guards and crossing signals must be obeyed; drivers must yield to pedestrians in a marked school crosswalk.

Pavement markings in school zones may include the word SCHOOL and yellow crosswalk lines to alert drivers.

Octagon = STOP; it is the only octagonal sign, so shape alone identifies it even when the legend is obscured.

Downward-pointing triangle = YIELD; it is the only triangle used for a regulatory sign.

Diamond = warning; yellow diamond signs warn of conditions ahead, and orange diamonds warn of work zones.

Pentagon = school zone or school crossing warning; the shape is used for school-related signs.

Round sign = railroad advance warning; a yellow circle with a black X and RR letters means a crossing is ahead.

Rectangle = regulatory or guide; vertical rectangles are typically regulatory, horizontal rectangles are typically guide.

Red means stop, yield, or prohibition; red is used on STOP, YIELD, DO NOT ENTER, and WRONG WAY signs.

Yellow means warning; fluorescent yellow-green is reserved for pedestrian, bicycle, and school warnings.

Green means guide or permitted movement; blue means motorist services; brown means recreation and cultural interest; orange means construction and maintenance.

Octagon = STOP; it is the only octagonal sign, so shape alone identifies it even when the legend is obscured.

Downward-pointing triangle = YIELD; it is the only triangle used for a regulatory sign.

Diamond = warning; yellow diamond signs warn of conditions ahead, and orange diamonds warn of work zones.

Pentagon = school zone or school crossing warning; the shape is used for school-related signs.

Round sign = railroad advance warning; a yellow circle with a black X and RR letters means a crossing is ahead.

Rectangle = regulatory or guide; vertical rectangles are typically regulatory, horizontal rectangles are typically guide.

Red means stop, yield, or prohibition; red is used on STOP, YIELD, DO NOT ENTER, and WRONG WAY signs.

Yellow means warning; fluorescent yellow-green is reserved for pedestrian, bicycle, and school warnings.

Green means guide or permitted movement; blue means motorist services; brown means recreation and cultural interest; orange means construction and maintenance.

Octagon = STOP; it is the only octagonal sign, so shape alone identifies it even when the legend is obscured.

Downward-pointing triangle = YIELD; it is the only triangle used for a regulatory sign.

Diamond = warning; yellow diamond signs warn of conditions ahead, and orange diamonds warn of work zones.

Pentagon = school zone or school crossing warning; the shape is used for school-related signs.

Round sign = railroad advance warning; a yellow circle with a black X and RR letters means a crossing is ahead.

Rectangle = regulatory or guide; vertical rectangles are typically regulatory, horizontal rectangles are typically guide.

Red means stop, yield, or prohibition; red is used on STOP, YIELD, DO NOT ENTER, and WRONG WAY signs.

Yellow means warning; fluorescent yellow-green is reserved for pedestrian, bicycle, and school warnings.

Green means guide or permitted movement; blue means motorist services; brown means recreation and cultural interest; orange means construction and maintenance.