Professor John Wann and his colleagues at Royal Holloway, University of London have recently measured the perceptual acuity of more than 100 children in primary schools, and calculated the speed of approach that they could reliably detect. Results suggest that while adult pedestrians can make accurate judgments for vehicles travelling up to 50mph, children of primary school age become unreliable once the approach speed goes above 20mph, if the car is five seconds away.

Click here to read a summary of this research written by a correspondent on the journal website and here to download the full report published in the journal Psychological Science.