Sleeping policemen

Road traffic casualties are known to show wide socioeconomic variation, but evidence as to what works to reduce them is in short supply. A new RCT published in the Journal of Epidemiology and Community Health assessed the effect of 20mph traffic speed zones in London. Researchers, who looked at data from 1987-2006, found that zones targeted in deprived areas only had a limited effect and that the socioeconomic gap continues to widen.