Safe Speed Forums

Knowledge of the amount of violence tolerated by the human body is essential when developing and implementing pedestrian safety strategies. When estimating the potential benefits of new countermeasures, the pedestrian fatality risk as a function of impact speed is of particular importance. Although this function has been analysed previously, we state that a proper understanding does not exist. Based on the largest in-depth, pedestrian accident study undertaken to date, we derive an improved risk function for adult pedestrians hit by the front of passenger cars. Our results show far lower fatality risks than generally reported in the traffic safety literature. This discrepancy is primarily explained by sample bias towards severe injury accidents in earlier studies. Nevertheless, a strong dependence on impact speed is found, with the fatality risk at 50 km/h being more than twice as high as the risk at 40 km/h and more than five times higher than the risk at 30 km/h. Our findings should have important implications for the development of pedestrian accident countermeasures worldwide. In particular, the scope of future pedestrian safety policies and research should be broadened to include accidents with impact speeds exceeding 50 km/h.

Aren't you guys being a wee bit harsh?

Pete, did you really expect " .. a strong dependence on impact speed is found, with the fatality risk at 50 km/h being more than twice as high as the risk at 40 km/h and more than five times higher than the risk at 30 km/h." to go down well on this forum?

It is true that Ashton (1982) included fatality rates at different speed ranges from pedestrian accident investigations in Great Britain during the 1960s and 1970s. However, Ashton et al. have specifically pointed out that, due to sample bias, these fatality rates did not give a fair description of the total population of accidents (Ashton et al., 1977; Ashton, 1982).

Besides, when on this forum has anyone seriously suggested that there isn't a strong relationship between impact speed and injury levels?

Nearly every time that weepje says that there is

No. He tries to argue that there's a strong relationship between injury levels and travelling speed, not impact speed.

Sophistry has reached a new level!

ANTI-SPEEDING FIGURES GREATLY EXAGGERATED

Campaign detailing probability of death at 30mph was based on 1970s numbers, DfT admits

The Department for Transport has revealed that the government's long-running Think! road safety campaign greatly exaggerated the chance of a pedestrian dying when being hit by a car at certain speeds.

The campaign suggested that a car travelling at 30mph had a 20 per cent chance of killing any pedestrian it hit, while at 40mph the probability of death rose to 80 per cent.

But these figures are based on data from the 1970s - since when both car safety design and emergency medical have improved markedly - and latest research now puts the chance of pedestrian death at 31 per cent at 40 mph and just 7 per cent at 30 mph.

Mike Penning, the road safety minister, said: "Road safety is a priority for the Government, but misleading statistics only serve to undermine our case, not help it".

What's most interesting is that the newer figures actually mean it is proportionately even more dangerous to pedestrians for cars to travel at 40mph in urban areas. The old figures meant you were four times more likely to be killed if hit by a car at 40mph than 30mph - the latest figures make death 4.5 times more likely if hit at 40mph, even though the probability of death or serious injury is severely reduced in both cases.

The Government criticised Labour for not releasing the updated information sooner, but accepted that the previous administration had originally used the figures in good faith.