Speed and the Pedestrian

Who actually dies on our roads? Not mostly drivers. Pedestrians are the largest single group killed, and riders and their passengers on motorcycles come next. The people with the least protection pay most of the cost.

The handbook's speed-management unit says it plainly: pedestrians face great risk when vehicles are driven at high speeds. The WHO describes the same relationship: above an impact speed of about 30 km/h a pedestrian's risk of death rises considerably, even more so for children and the elderly, and between 50 and 65 km/h it rises about four and a half times. A few km/h at town speeds decides whether a pedestrian lives.

The stopping table shows why. The WHO puts it in one line: in the distance a 30 km/h car can stop, a 50 km/h car is still driving. Imagine a child steps out 18 metres ahead of you:

• At 30 km/h, your dry stopping distance is about 18 metres. You stop, just.
• At 50 km/h, your reaction distance alone is about 21 metres. After 18 metres you haven't even started braking. You hit the child at the full 50 km/h.

The difference between those two outcomes is 20 km/h and about one second of attention. That is why town limits are set where they are, and why The Vulnerable Road User Picture puts pedestrians at the centre of Kenya's road deaths. It is also why hazard perception matters most where people walk. Seeing the child early lets you be at 30 instead of 50 when it counts.