Wet-Leaf Curve on Rock Creek Parkway at Night
It is 9:20 p.m. in late November and you are southbound on Rock Creek Parkway. Light rain has been falling for an hour, and wet leaves are packed along the edge of the road. A yellow diamond sign ahead shows a curve to the left with a 25 mph advisory speed plaque, followed by several chevron signs pointing left. Your speedometer reads 35 mph. The posted speed limit upstream was 30 mph. A car is following about one second behind you with its high beams on. The pavement in the curve looks darker and slicker than the straightaway, and the shoulder is narrow with a low stone wall on the right. You see a flash of movement in the trees on the left but cannot tell whether it is a deer.
1. What does the yellow diamond curve sign and the 25 mph plaque legally require, and why is 35 mph a poor choice here even though it is above the advisory speed?
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The yellow diamond is a warning sign: it alerts you to a curve ahead. The 25 mph plaque is an advisory speed, meaning the recommended maximum for the curve under good conditions; it is not the same as a posted regulatory speed limit. Even so, 35 mph is a poor choice because the advisory assumes dry pavement and good visibility. Here you have rain, wet leaves, darkness, a narrow shoulder, and a stone wall close to the travel lane. Those conditions reduce traction and increase stopping distance. You should slow to at or below 25 mph before entering the curve, not brake hard in the middle of it, and use the chevrons to track the curve's direction.
2. The movement in the trees could be a deer. How should you adjust your speed, lane position, and scanning, and what should you do if a deer steps into the road?
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Treat the possible deer as a reason to cover the brake and reduce speed further. Scan the left tree line and shoulder, not just the center of the lane, and use high beams when there is no oncoming traffic. Stay centered in your lane rather than drifting toward the stone wall or the oncoming lane. If a deer steps into the road, brake firmly in a straight line and keep control; do not swerve into oncoming traffic or into the wall. A controlled stop or low-speed impact is usually safer than a violent swerve. After the deer passes, continue scanning because deer often travel together.
3. The tailgater with high beams is making you uncomfortable. What is the safest response in the curve?
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Do not speed up to create distance while you are in the curve. Maintaining a predictable speed at or below the advisory speed is more important than satisfying the driver behind you. Increase your following distance ahead so you can slow gradually rather than braking abruptly. If there is a safe pullout after the curve, signal early and let the tailgater pass. Otherwise, continue steadily and avoid brake-checking. For the high beams in your mirror, use the night mirror position or tilt the mirror; do not stare into it.