Correlation between car weight and fatal collisions, says study

Average car weight in the UK is increasing, which may lead to a rise in fatal collisions if the trend continues. Reducing car weight could mitigate the severity and frequency of collisions

Average Annual Fatal Collisions per 1 Million Cars by Weight Category (2019-2023)

Average Annual Fatal Collisions per 1 Million Cars by Weight Category (2019-2023)

A recent study has highlighted the correlation between car weight and fatal collisions, suggesting that it is likely that fatal collisions will increase if the trend of rising car weight continues. 

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This research, funded by the Rees Jeffreys Road Fund for the 2024/25 Future Transport Visions Group Initiative, used data from the Department for Transport. Ruth Carlson, Nima Dadashzadeh, Mustafa Ekmekci, Samuel Johnson, William Petty, Mary Sizemore, Amy Walker, Tom Morris took part in the research.

The study looks at collisions involving cars between 500-2500kg, pedestrians, and cycles. The cars involved in the collisions have been matched to a car make and model which has been matched to a kerb weight in kg. The car make and model, as well as collision data has been provided by the DfT. The kerb weight data has been supplied by a third party.

This study finds that heavier cars are more likely to be involved in fatal collisions and average car weight in the UK is increasing, which may lead to a rise in fatal collisions if the trend continues. Reducing car weight could mitigate the severity and frequency of collisions. This summary note will be followed by a further academic study later in 2025.