Warning Signs
Warning Signs
Warning signs alert you to a change or hazard ahead. The Guam exam tests whether you recognize the standard yellow diamond, read advisory plaques correctly, and adjust speed before the hazard rather than at it. Guam uses MUTCD shapes and colors, so a yellow diamond has the same meaning on a coastal road as on a mainland highway.
Core rules
- Warning signs are normally yellow diamonds with black symbols or words. Yellow means caution, not a legal stop or speed limit.
- A yellow plaque beneath a warning sign, such as “35 MPH,” is an advisory speed for that curve or ramp. It is not a posted regulatory limit, but driving faster can be unsafe and can support a citation for driving too fast for conditions.
- Common symbols include reverse curve, sharp right or left turn, crossroad, side road, merge, lane ends, slippery when wet, hill, deer, and traffic signal ahead.
- Fluorescent yellow-green is used for pedestrian, bicycle, and school warnings; it is not the same as construction orange.
- Warning signs are placed in advance of the hazard. The distance varies with road speed; do not expect the curve at the sign itself.
- A “STOP AHEAD” warning tells you to prepare to stop; the stop line and STOP sign still control the intersection.
Worked example
You see a yellow diamond showing a curve arrow with a “30 MPH” plaque, then a second yellow sign showing a slippery-road symbol. Your speed is 50 mph. The 30 mph plaque is advisory: slow before the curve, especially in rain. The slippery-road sign warns that the curve may have less traction. You should brake smoothly before the curve, not midway through it, because braking on a wet curve can cause a skid. The plaque does not create a 30 mph legal limit, but 50 mph in a posted 30 mph advisory curve in rain is evidence of unsafe speed.
Traps
Do not obey an advisory plaque as if it were a white speed limit sign, and do not ignore it as meaningless. Do not expect warning signs to be placed at the hazard. Do not confuse a yellow pedestrian warning with a school pentagon. Do not assume a warning sign gives you the right of way at a merge.