Warning Signs
Warning signs alert you to a change in conditions ahead; they do not usually create a legal command, but ignoring them is how drivers get surprised. The exam tests the standard yellow diamond, the meaning of symbols, and the difference between a warning and a regulatory sign.
Core rules
- Standard warning signs are yellow diamonds with black symbols or words.
- Fluorescent yellow-green is used for school, pedestrian, and bicycle warnings so they stand out.
- Common messages: curve or reverse curve, hill, lane ends, merge, signal ahead, pedestrian crossing, deer, slippery when wet, and intersection ahead.
- A yellow plaque with a speed such as 40 MPH is an advisory speed for the condition, not a posted legal limit.
- Warning signs are placed in advance of the condition; the distance gives you time to slow down before the feature, not after you are in it.
Worked example
You see a yellow diamond showing a reverse curve with a 40 MPH plaque. The diamond tells you the road bends right then left; the plaque tells you 40 MPH is the speed at which the curve can be taken comfortably under good conditions. The correct response is to slow to at or below 40 before entering the first curve, not to brake hard in the middle of it. If conditions are wet or dark, a lower speed is appropriate.
Traps
A yellow sign is not permission to proceed without caution, and it is not a regulatory limit. Candidates lose marks by treating the advisory speed as enforceable in the same way as a white SPEED LIMIT sign. Also watch for fluorescent yellow-green: it is still a warning color, not a construction color. Orange means work zone; yellow means general warning.