Dead Robots, a Faded Stop Line and a Pedestrian in Dark Clothes
It is 22:40 during load-shedding and you are driving a light delivery vehicle at 55 km/h in a 60 km/h zone. Ahead is a four-way intersection where the traffic signals are completely dark. On your approach the stop line is so worn you only see it at the last moment, a solid barrier line runs on your side for the last 200 m, and a pedestrian crossing lies 15 m before the intersection. Street lighting on that corner is out. A minibus taxi is coming from your right at roughly 70 km/h with only one headlight working. As you get within about 20 m, a person in dark clothing steps onto the crossing. Your headlights are on dipped beam.
1. Describe exactly how you should negotiate this intersection with the signals dead, and explain what the faded stop line and the barrier line require of you.
Read the worked answer
A dark signal is not a green light and gives nobody right of way. The correct discipline at a signalised intersection that is out of order is to treat it as a four-way stop: come to a complete halt, establish eye contact or at least a clear gap, and proceed only when you can do so without making anyone brake. Where the intersection is effectively uncontrolled, the default is to yield to traffic approaching from your right - which in this case is the taxi - but you do not surrender the stop itself; you stop first and then decide.
The faded stop line still marks the legal place to stop even though you can barely see it. Stop before it, and never stop on the pedestrian crossing, because that is exactly where a person in dark clothes will appear from.
The solid barrier line forbids you from crossing or straddling the centre line. That rules out swinging wide into the oncoming lane to get around a stationary vehicle, and it rules out overtaking a queue that has formed at the dead signal. Approach in a low gear, slow enough that you could stop within the distance you can actually see, and expect the taxi to do the wrong thing.
2. Using stopping-distance reasoning, decide whether you could have stopped for the pedestrian, and say what that tells you about your speed choice.
Read the worked answer
Convert the speed: 55 km/h ÷ 3,6 ≈ 15,3 m/s.
- Thinking distance at a realistic 0,8–1,0 s reaction time = 12–15 m.
- Braking distance on wet tar (friction coefficient around 0,5): v² ÷ (2 × 0,5 × 9,8) ≈ 234 ÷ 9,8 ≈ 24 m.
- Total ≈ 36–39 m.
The pedestrian appears at about 20 m, with the crossing itself 15 m ahead of the intersection. Even on dry tar (coefficient about 0,75, braking distance ≈ 16 m) the total is around 28–31 m. Either way, the stop was impossible before you ever saw the person.
That is the real finding: this was not a reaction failure, it was a speed-and-visibility failure. Dipped beam throws usable light roughly 45 m ahead in the dark, and in a blacked-out suburb with a worn stop line and an unlit crossing, your safe speed is set by what you can see and stop within, not by the number on the pole. At 40 km/h your total stopping distance drops to roughly 25 m; at 30 km/h to about 16 m. The pedestrian crossing must be kept clear and pedestrians already on it have right of way, but you cannot yield to someone you only detect with 20 m to spare.
3. The taxi from the right is closing fast and the pedestrian is now on the crossing. Set out your immediate actions in order, and explain the risk you are managing with each one.
Read the worked answer
- Brake firmly and progressively, not in a panic lock-up. On wet tar a locked wheel removes your steering, and steering is the only thing that may save the pedestrian. Cadence or threshold braking keeps the option open.
- Steer only if it does not take you across the barrier line or into the taxi's path. A swerve to the right is a swerve into a 70 km/h minibus; the barrier line confirms that space is not yours to use.
- Sound the horn early and briefly to warn both the pedestrian and the taxi. A short blast communicates; a long one only communicates panic.
- Do not enter the intersection on the assumption that the taxi will stop. Assume it will not. Stopping in the intersection is how a four-way-stop collision happens.
- Once stopped, stay stopped until the crossing is clear and you have seen the taxi actually slow or pass. Creeping forward to "claim" your turn is how vehicles collide at dead signals.
The judgement being tested is that your priority order is pedestrian first, taxi second, your own schedule never. The moment you treat the dark signal as permission to keep momentum, you have handed the outcome to a driver with one headlight.