Warning Signs: Curves, Intersections, Road Narrowing, Hills, and Surface Conditions
Warning signs alert you to a change ahead so you can adjust speed and lane position. In Missouri they are usually yellow diamonds with black symbols; a yellow rectangle with black wording may add distance or a specific hazard. The exam tests the hazard named, the direction it affects, and what the driver should do.
Core rules
- Curves are shown by a curved arrow; reverse curves by an S-shaped arrow. Check the arrow direction: it tells you which way the road bends.
- Intersections use crossroad, side-road, T-intersection, or Y-intersection symbols. A side-road sign shows whether the road enters from the right or left.
- Road narrowing symbols show the road losing width on the right, left, or both sides. Do not drift; maintain lane position.
- Hills warn of limited sight distance or a steep grade. Slow-moving vehicles may be ahead; passing may be unsafe.
- Surface conditions include slippery when wet, loose gravel, and uneven pavement. Rain, ice, or gravel reduces traction.
- An advisory speed plaque gives a recommended safe speed for the hazard. It is not a legal speed limit, but exceeding it can be unsafe, especially on curves.
Worked example
A driver sees a yellow diamond with a curve arrow, a "35 MPH" plaque, and a "SLIPPERY WHEN WET" sign. The correct response is to slow to about 35 before the curve, avoid hard braking inside it, and increase following distance. The posted regulatory speed may be higher, but the advisory plaque reflects the curve's safe speed.
Traps
A warning sign does not require a stop. The advisory speed is not the same as the legal limit. Do not wait until you are in the curve to slow; brake before it. A "road narrows" sign does not mean the lane ends immediately.