Advisory Speed and Trailer on County Road 9
On a wet October morning, you are westbound on County Road 9 near Lanesboro, Minnesota, descending into the Root River valley. The road is a two-lane county highway posted 50 mph. You are towing a single-axle utility trailer with about 1,200 pounds of equipment. Ahead, a yellow diamond sign shows a left curve and a black plate below reads '30 MPH.' Beyond it, three chevron signs point left along the outside of the curve. The pavement is covered with wet leaves, and the sun is low behind you. A pickup ahead taps its brakes before the curve. Your trailer has no trailer brakes. You see a gravel pull-off 150 feet before the chevrons and a deer carcass on the shoulder. The curve radius is tight enough that you cannot see beyond the guardrail.
1. What does the 30 MPH plate under the left-curve sign mean, and how should it change your speed with a trailer and wet leaves?
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The 30 MPH plate is an advisory speed, not a regulatory speed limit. It tells you that 30 mph is the recommended maximum for the curve under good conditions-dry pavement, no trailer, a passenger car. It is not a legal limit you may always drive, and it is not a guarantee that 30 is safe in your situation. You are towing 1,200 pounds with no trailer brakes, on wet leaves, downhill, with a blind guardrail. Those factors increase stopping distance and the chance of trailer sway. Slow down before the curve-well before the chevrons-to perhaps 20–25 mph, shift to a lower gear, and avoid hard braking while turning. The advisory plate should be treated as a warning to slow more, not as a target to match.
2. Why are the chevrons on the outside of the curve, and what should you do if you cannot see the next one?
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Chevrons mark the direction of the turn and the outside edge of the curve, so they are placed where a driver who drifts wide would otherwise leave the road. They confirm that the road turns left and help you judge the curve's sharpness when the guardrail or trees block your view. If you cannot see the next chevron, your sight distance is shorter than the curve; that is a sign to slow further, not to follow the pickup closely. Keep your lane position steady, look ahead toward the next visible chevron, and use gentle steering. With a trailer, a sudden correction can cause sway; ease off the accelerator rather than jerking the wheel. If the trailer begins to sway, do not brake hard-reduce speed smoothly.
3. The pickup ahead brakes sharply just before the curve. Should you close the gap to use its brake lights as a guide?
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No. The pickup's brake lights can tell you that it is slowing, but following closely reduces your view and your margin. Your rig is longer and heavier, the leaves are wet, and the trailer has no brakes, so your stopping distance is greater than the pickup's. Increase the gap, brake early and gently, and let the trailer track straight before you enter the curve. Use the pickup as information, not as a shield. If it stops suddenly, you need space to stop without skidding. A safe following distance on this wet downhill approach is more than the normal dry-road gap.