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expert reaction to study suggesting pedestrians may be twice as likely to be hit by electric/hybrid cars as petrol/diesel ones

A study published in the Journal of Epidemiology and Community Health looks at electric/hybrid cars and pedestrian safety. 


Prof Benjamin Heydecker, Emeritus Professor of Transport Studies, University College London (UCL), said:

“The authors seek to quantify the relationship between the risks to pedestrians of being struck by vehicles powered by each of electric and hybrid-electric (E-HE) and internal combustion (ICE). Their hypothesis is that because of their lower noise emission, the E-HE vehicles confer greater risk than do ICE ones.

“The authors consider Urban (U) and Rural (R) settings separately: this is justified by the greater proportion of vehicle distance in Urban settings that is travelled by E-HE than in Rural settings.

“The authors’ estimates of risk ratio (E-HE / ICE) are substantial (in the order of 2 – 3 depending on the setting), with greater risk ratio in Urban settings.

“The estimates of risk for E-HE vehicles are subject to the reservation that the number of vehicles for which propulsion code was missing (22,829) greatly exceeds that for E-HE (1,652). This means that a greater tendency for E-HE to be recorded as missing, which would reduce the estimate of risk ratio, could do so substantially.

“The authors’ review notes that the US NHTSA found that the odds of an E-HE vehicle causing a pedestrian injury were greater than for ICE, whilst the UK DfT found the rates for E-HE were lower than for ICE. Whilst ORs can differ from rate ratios as the authors note, such differences would not usually admit a substantiated change in sign of effect.

“Whilst the power units of E-HE vehicles will emit less particulates, the remaining sources of brake (pad and disc) and road/tyre interface will remain. The additional mass of batteries in E-HE vehicles will tend to increase particulate emissions from road/tyre interface. E-HE vehicles will therefore not eliminate particulate emissions.”


Prof Kevin McConway, Emeritus Professor of Applied Statistics, Open University, said:

“This is an interesting study but it does have limitations. Several are pointed out by the researchers in the research paper.

“I think the most important limitation is that the results tell us that collision rates with pedestrians are higher with electric or hybrid cars than with cars with internal combustion engines, but the study can’t tell us why the rates are higher. The researchers suggest that it could be because pedestrians can’t hear the electric cars well, in urban settings. That’s certainly a plausible possibility.

“But there are other possibilities. If electric and hybrid cars are, on average, driven differently than other cars, perhaps because they are used for different purposes or have different types of driver, then that could be a reason for the different collision rates, rather than the actual type of propulsion or the sound it makes. The researchers mention that drivers of electric and hybrid cars tend to be younger, and that younger, inexperienced drivers tend to have more collisions, but that’s not the only possible reason that’s not directly to do with the car’s engine type. This type of research can’t distinguish between all these possibilities, and that’s why further research would be needed.

“Another possible issue is that the data used is quite old now, from 2013-17. The researchers point out that it’s the latest available, but perhaps pedestrians and drivers have changed their behaviour as electric cars have become more common on the roads.”



Pedestrian safety on the road to net zero: cross-sectional study of collisions with electric and hybrid-electric cars in Great Britain’ by Phil J Edwards et al. was published in Journal of Epidemiology and Community Health at 23:30 UK Time Tuesday 21 May 2024. 


DOI: 10.1136/jech-2024-221902



Declared interests

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  My quote above is in my capacity as an independent professional statistician.”

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