Warning Signs: Curves, Intersections, Lane Transitions, and Road Conditions
Warning signs: yellow diamonds and what they predict
Warning signs alert you to a change ahead-curves, intersections, lane mergers, surface hazards. Most are yellow diamonds with black symbols. A curve sign with an arrow shows direction; a plaque beneath it may show an advisory speed, such as 35 MPH. That is the recommended speed for the curve, not a legal maximum; if conditions are wet or icy, go slower. Chevron signs (black on yellow) mark the outside of a sharp curve and are placed to be followed, not ignored.
Intersection warnings include crossroad, side road, T-intersection, and roundabout signs. Lane-transition signs show a lane ending or merging; the symbol with a curved arrow tells you which lane must merge. Road-condition warnings cover slippery when wet, loose gravel, pavement ends, steep grade, and deer crossings. A "TWO-WAY TRAFFIC" sign warns that a one-way road is becoming two-way-stay right.
Worked example: A yellow diamond shows a right curve and a 40 MPH advisory plaque. The posted limit is 55. In dry weather, 40 is a reasonable target; in rain, slow further. You are not automatically illegal at 45, but if you lose control, the advisory speed is evidence you were going too fast for conditions.
Traps: confusing warning yellow with construction orange; missing a "lane ends" symbol and drifting into a closing lane; treating an advisory speed as enforceable exactly; and overlooking a second plaque such as "TRUCKS USE LOW GEAR." Warning signs do not grant right-of-way-they only tell you what is coming.