High Beams and a Tractor on a County Road
At 10:15 p.m. in late November, Ethan is driving east on a two-lane Iowa county road posted 55 mph. The pavement is dry and the sky is clear. A pickup approaches from the west with its high beams on and does not dim them. Ahead in Ethan's lane, a farm tractor with a slow-moving-vehicle triangle and amber flashers is crawling at 15 mph. The center line on Ethan's side is a solid yellow for the next quarter mile; beyond that, it becomes broken for a short stretch before a crest in the road. Ethan is 40 feet behind the tractor, and the oncoming pickup is closing fast. Ethan's own high beams are on. He is driving a small sedan with good brakes and new tires.
1. What should Ethan do about the oncoming pickup's high beams in the next few seconds?
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Ethan should dim his own high beams to low beam as soon as the pickup is within about 500 feet, even though the other driver is not dimming. Iowa requires dimming for oncoming traffic, and retaliating with high beams only makes two blinded drivers. To cope with the glare, he should look toward the right edge of his lane and the fog line, not directly at the lights, and he should ease off the accelerator slightly so he has more time to react. He should not flash his high beams or brake hard, because the tractor is close ahead and a panic move could cause a rear-end crash or a loss of control. Once the pickup passes, he can return his attention to the lane and reassess the tractor.
2. Can Ethan legally pass the tractor in the next quarter mile? If not, what following plan should he use?
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No. A solid yellow line on his side means no passing, and the crest ahead is an additional sight-distance problem even where the line is broken for a short stretch. At 15 mph the tractor is moving about 22 feet per second, and 40 feet is less than two seconds of following distance, which is too close for a rural road at night. He should back off to at least three or four seconds, keep his low beams on, and watch for the tractor's turn signals or hand signals. He should not start a pass unless he has a broken line, a clear view over the crest, no oncoming traffic, and enough open road to complete the pass before the next no-passing zone.
3. Suppose the line becomes broken and the oncoming pickup has passed. What checks should Ethan make before passing, and what should he do if the tractor speeds up?
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Before passing, Ethan should check his mirror and blind spot, signal, and make sure no car behind him has already started to pass. He should confirm that the broken line continues long enough, that the crest is far enough away, and that the oncoming lane is clear for the entire maneuver. He should accelerate smoothly, not exceed 55 mph, and return to the right lane only when he can see the tractor in his mirror. If the tractor speeds up or the gap closes, he should abort the pass by slowing and pulling back in behind it rather than racing the engine or forcing the pass. A failed pass is safer than a head-on crash.