Advisory Speed Plaque, Chevrons, and a Wet Curve at Dusk
Just after sunset, light rain has been falling for 20 minutes on a two-lane rural road in Kent County, Delaware. The posted speed limit is 50 mph. You are following a farm truck at what had been a comfortable distance when the road enters a sequence of signs: a yellow diamond showing a curve to the right with a yellow rectangular plaque reading 30 MPH mounted directly beneath it; three black-on-yellow chevron signs spaced along the outside of the bend; a yellow diamond reading SLIPPERY WHEN WET; and, at the far end of the curve, a yellow diamond with a NARROW BRIDGE symbol and black-and-yellow object markers at both bridge ends. There is no shoulder - a drainage ditch runs along the right edge - and the asphalt is glazed with water. The farm truck brakes abruptly to about 25 mph partway around the bend, and an oncoming pickup with high beams on drifts slightly across the centerline. Your headlights are reflecting off the wet pavement, and you can see the bridge deck glistening ahead.
1. Is the 30 MPH plaque an enforceable speed limit? How should it govern your speed tonight?
Read the worked answer
No. The plaque sits under a yellow diamond, and yellow means warning, not regulation. A yellow rectangular plaque under a warning sign is an advisory speed - the recommended maximum speed for the curve under favorable conditions. The enforceable posted limit remains 50 mph.
That does not make the plaque optional advice. Delaware's basic speed rule requires you to drive at a speed reasonable and prudent for conditions, and the advisory is strong evidence of what that speed is. Tonight the conditions are the opposite of favorable: rain, darkness, glare, and a wet, glazed surface. A crash at 45 mph in this curve would be very hard to defend as reasonable when the state's own sign says 30.
Practical plan: brake before the curve sign while the car is still straight, aim to enter the bend at or below 30 mph, use light steady throttle through the curve, and avoid hard braking mid-corner where the tires have little grip left for both turning and stopping. Treat 30 as a ceiling, not a target, and drop below it because of the water.
2. What do the chevron signs tell you, and how should they change your steering, lane position, and eye placement?
Read the worked answer
Chevrons (black on yellow, rectangular, mounted low) mark the outside of a sharp change in alignment and show the direction of the turn. Their presence alongside a curve-plus-advisory-speed assembly tells you the curve is sharper than an ordinary bend: the advisory plaque alone would often be enough, so chevrons mean the geometry needs extra emphasis.
How to use them:
- Track them with your eyes - look through the curve to the furthest visible chevron, not at the one beside your bumper. Where you look is where the car goes.
- Stay right of the centerline. The oncoming pickup is already drifting over it, so hold a lane position a little right of center but still clear of the ditch edge.
- Do not brake hard mid-curve. If you enter too fast, ease off the throttle and brake gently in a straight line as soon as the road allows.
- Keep steering if the chevrons continue. When chevrons keep appearing past the point where you expected the curve to end, the curve is continuing or tightening; many drivers straighten up early and run off the outside edge.
A single chevron is a direction cue; a series of them is a statement about how much attention this bend deserves.
3. The farm truck brakes hard to 25 mph and the oncoming high beams are in your eyes. What is your plan for the next several hundred feet?
Read the worked answer
Three problems are stacked: reduced grip, reduced sight distance, and reduced night vision.
- Following distance. At 50 mph you cover roughly 73 feet per second. In rain at night, more than the normal gap is needed - aim for at least four seconds, and more behind a truck whose brake lights you may lose in spray. If the truck stops, you need room to stop without swerving into the ditch.
- The truck is your early warning. Its abrupt braking to 25 mph suggests something ahead: the curve, standing water, or the bridge. Reduce speed now rather than matching its braking at the last second.
- Glare. Do not stare at the oncoming headlights. Shift your gaze to the right edge line and the object markers to hold your lane, while using peripheral vision for the oncoming vehicle. Do not flash your high beams in retaliation.
- SLIPPERY WHEN WET and NARROW BRIDGE. Slow before the bridge, not on it - bridge decks and expansion joints are slicker than asphalt and often narrower than the approach. Enter centered and without braking or steering inputs.
- No passing. With no shoulder, a blind curve, and oncoming traffic, there is no legal or safe overtake; the correct response to a slow truck is patience and space.