Research in 1998 showed that the reduction of some United Kingdom speed limits to had achieved only a 1 mph drop in speeds and no discernible reduction in accidents; 20 mph speed limit zones, which use self-enforcing traffic calming, achieved average speed reductions of 10 mph; child pedestrian accidents were reduced by 70% and child cyclist accidents by 48%. Zones where speeds are set at 30 km/h (or 20 mph) are gaining popularity as they are found to be effective at reducing crashes and increasing community cohesion.