Dusk, a Tractor and a Blind Crest
It is 18:40 in late October. You are riding on a rural road with an 80 km/h limit, following a tractor towing a trailer of hay at about 25 km/h. Three cars are behind you, the first sitting close. You have been behind the tractor for 1.5 km. Rubble walls line both sides. Ahead, the road climbs to a blind crest about 200 m away, and a farm track joins from the left about 80 m ahead. Overhanging branches on the right limit your view of oncoming traffic to about 120 m. Your headlight is on dipped beam. The trailer has no working rear lights and no reflective triangle. The sun has just set behind you, so the sky ahead is still bright while the road surface itself is in shadow. Your machine is a 35 kW naked bike, well maintained, with ABS.
1. Decide whether to overtake now, showing the reasoning and the numbers rather than a gut feeling.
Read the worked answer
No - and the numbers show why it is not close.
Speeds
- You at 80 km/h = 22.2 m/s. Tractor at 25 km/h = 6.9 m/s. Closing speed if a vehicle comes over the crest = 22.2 + 22.2 = 44.4 m/s head-on, or 22.2 + 6.9 = 29.1 m/s relative to the tractor.
Distance available
- Useful forward view: about 120 m to the point where the crest and the branches cut off sight of oncoming traffic. That is the hard limit - beyond it you are committed and blind.
Distance needed
- Overtaking a 25 km/h vehicle from 30 km/h to 70 km/h on a 35 kW bike takes roughly 4–5 seconds and covers about 70–90 m travelled, plus the return to your side.
- Oncoming traffic at 80 km/h eats the 120 m of view at 22.2 m/s. So the oncoming lane is only verifiably clear for about 5.4 seconds - and that is assuming a vehicle is not already just beyond the crest.
Other disqualifiers, which alone would settle it
- The farm track at 80 m is a live conflict point: a vehicle could emerge into the space you plan to use.
- The trailer is unlit and unreflective, and the road is in shadow while the sky ahead is bright - the worst possible contrast. A following driver may not see the trailer at all.
- The rubble walls leave no escape route if the overtake goes wrong. There is no hard shoulder, no gap, no run-off.
Decision: hold position, stay back, and wait for the crest to be behind you and for a section with a clear view and a defined escape route. A 1.5 km delay is not a reason; it is a sunk cost.
2. Having decided not to overtake, how do you position and manage the situation, including the three cars behind?
Read the worked answer
Positioning
- About three seconds behind the trailer, which at 25 km/h is roughly 20–21 m. Closer than that and you lose the sight line around the tractor; further and the cars behind will try to fill the gap.
- Offset to the left of the tractor's track, not directly behind it. This does two things: it lets you see past the outfit to the road ahead, and it puts you where the following cars can see you rather than where they expect a shadow.
- Not over the centre line - you are not overtaking, and a bike sitting on the centre line at dusk invites a following driver to read it as a signal that the road is clear.
- Dipped beam on, and consider that the bright sky ahead already makes you hard to pick out; a high-visibility outer layer matters more at this hour than at midday.
Managing the cars behind
- Do not wave them past. You are not a marshal; if you wave and they crash, you have created the situation. Let them make their own decision.
- Do not speed up to close the gap to stop them overtaking. That puts you closer to the unlit trailer.
- If the first car is tailgating, the safe response is to increase your own following distance to the tractor slightly, so that if the tractor brakes you have room to slow progressively rather than braking hard with a car on your mudguard.
- If it becomes intolerable, the correct move is to pull over where it is genuinely safe - a gateway or a wide verge with good visibility - signal early, slow, and let the queue go. Not on a blind crest, not against a rubble wall.
The principle: you cannot control the cars behind, only the gap in front of you and the clarity of your own intentions.
3. The tractor now signals right towards the farm track 80 m ahead. How do you interpret that signal, and what do you do?
Read the worked answer
Treat the signal as information, not as an instruction, and expect the manoeuvre to be worse than the signal suggests.
What the signal probably means
- The tractor intends to leave the road into the track on the left of the picture - but it is on your side, so in left-hand traffic a right turn means it will cross the oncoming lane.
- A tractor towing a hay trailer needs a wide sweep. It will very likely move left before it turns right, which means it may briefly occupy the whole width of the road, and the trailer will cut the corner rather than follow the tractor's path.
What you do
- Do not overtake. Overtaking a vehicle that is turning right, on the side it is turning towards, is one of the classic collision patterns - and here the trailer will be swinging across your path even after the tractor has left the road.
- Ease off and increase the gap to 4–5 seconds. The tractor will slow sharply, possibly to walking pace, and you do not want to arrive at its rear wheel as it swings.
- Watch the trailer, not the tractor. The tractor will be gone from your path before the trailer is; the trailer is the part that hits you.
- Watch for a following car deciding to overtake you both at exactly the moment the road is blocked. A shoulder check before you brake is worth more than a mirror glance.
- Be ready to stop and to hold your line; the oncoming lane may be briefly blocked by the tractor's sweep, so do not plan to use it.
Once the outfit is clear of the road, you have a decision: continue, or use the moment to let the three cars past. If the track entrance gives you a clear view and a safe place to pause, that is the natural point to reset the situation behind you.