Calls to lower speed limits as a means of improving safety in school zones may actually make things worse, according to an analysis of UK Department for Transport (DfT) statistics. Road safety expert Paul Smith, founder of Safe Speed, points out that accidents are more likely to be fatal or more serious in a 20 MPH zone than in a 30 MPH zone.

"The authorities continue to treat road safety as a problem of vehicle physics when in fact it is a complex problem of human psychology," Smith explained. "There's no indication that any of the 'speed kills' policies have made our roads safer. Speed cameras, traffic calming, speed limit reductions and so on have all been rolled out across the country with no significant reduction in road deaths or road crash hospitalizations."

The DfT report Road Casualties Great Britain: 2005 shows that accidents in 20 MPH zones have an 11.85 percent chance of involving a fatality or serious injury while in 30 MPH zones that chance is 10.26 percent (Table 13). Smith suggests the reasons why 20 MPH zones are more dangerous is complex and that the simplistic solutions offered by the transportation bureaucracy is making things worse by, for example, forcing motorists to watch their speedometer instead of the road ahead.

"Far too often they claim that 'it's obvious' that a given intervention should work." Smith said. "As is common with modern road safety interventions this has not been investigated. They do it because they believe it should work."