Crosswind and Trailer Sway Behind a Semi
Dan is riding a 400 cc bike west on Highway 1 at 100 km/h. A strong crosswind blows from the south at 30 km/h. He is following a semi-trailer with about a two-second gap. The trailer begins to sway side to side, and a piece of retread appears on the right shoulder. Dan wants to pass before the next hill because he has been stuck behind the truck for 20 km. His lane position is currently in the left wheel track. He wears a textile jacket and a full-face helmet. The truck's left turn signal is not on. A line of three cars is behind Dan. The wind is pushing his bike toward the centre line.
1. What should Dan do about his following distance and lane position before deciding to pass?
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Dan should first increase his following distance. Two seconds is too close for a 100 km/h highway, especially behind a swaying trailer that can shed debris or brake abruptly. He should drop back to at least four seconds and move away from the centre line if the crosswind is pushing him there, but he must not hide in a blind spot. The left wheel track is a reasonable lane position, but he needs to stay visible in the truck's mirrors and leave room for wind gusts. The sway is a warning that the truck may move unpredictably; the retread shows debris is already present.
2. Should Dan pass now? Consider the trailer sway, the cars behind him, and the upcoming hill.
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Dan should not pass now. A trailer that is swaying may cross the lane line or shed more debris, and passing would put him alongside a vehicle whose driver may be struggling. He also has three cars behind him, which can create pressure, but that is not a reason to take a risky gap. He should wait until the trailer is stable, he has a clear view and enough distance, and he can complete the pass without exceeding the limit. If the sway continues, backing off further is better than trying to beat the truck before the hill.
3. How should Dan handle the wind blast and the debris hazard if he eventually passes?
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When he does pass, he should anticipate the wind blast as he leaves the truck's shelter and enters the open crosswind. He should be ready for the bike to move and use smooth steering, not a sudden correction. He should also watch the debris on the right shoulder and avoid swerving into the truck or the centre line. A firm, steady grip and a pre-planned lane position help. If the wind is too strong for a safe pass, he should stay back. The retread should be treated as a hazard even if it looks stationary.