Table 1

Influence of traffic calming measures on injuries

CitationStudy groupStudy type (level of evidence)OutcomeKey resultsComments
Elvik (2001)33 studies of traffic calming measures were included, all of which employed some version of a before-and-after study design. All studies were non-experimentalSystematic review, meta-analysis (level 2a)Effects of traffic calming on reported injury accidentsOn average, traffic calming measures reduced injuries by to 15% (95% CI −17% to −12%). Studies were weighted according to study design and the overall effect for studies with matched comparison groups was a 12% reduction, while studies with a simple before-and-after design found a 36% reduction in injury accidentsSome of the studies did not include a control group. Separate effects on morbidity/mortality not available. Single authorship means that it is not clear whether more than one independent reviewer extracted the data
Duperrex et al (2002)15 randomised controlled trials of pedestrian safety education programmes. Study participants were children in 14 studies and institutionalised adults in oneCochrane systematic review (level 1a)Preventing pedestrian-motor vehicle collisions and in changing behaviour, attitude and knowledge of pedestriansThe relative probability of trained pedestrians behaving correct in traffic compared to non-trained ones ranged between 0.49 and 9.29. Safety education improved the attitude/intentions of pedestrians by a standardised mean difference of 0.17 to 1.48 The impact of educational programmes on participants' knowledge was inconsistent across studiesNone of the trials assessed the effect of pedestrian safety education on pedestrian injury Allocation concealment was adequate in three trials, outcome assessment was blinded in eight. Most of the studies lost large numbers of participants to follow up
Dowswell et al (1996)Health promoting interventions to reduce unintentional injuries in children aged 0–14 yearsSystematic review, narrative form, update of previous review Differences in interventions and outcome measures in the trials meant that a meta-analysis was not carried outHealth promotion interventions to reduce childhood unintentional injuriesTraffic calming was among the interventions found effective in reducing injury. Few studies were found to have achieved behaviour changes in child pedestrians and fewer still were able to link child education campaigns with changes in casualty ratesNo information on the number of included studies and the methodological rigour of these Lack of effect sizes makes it difficult to compare the described interventions
Roberts et al (1994)Child pedestrian injury rates, costs of child pedestrian education, costs of implementing traffic calmingCost and efficacy analysis of traffic education and traffic calming measuresEstimates of lives saved in New Zealand if money spent on traffic safety education was instead used on traffic calming measuresUsing the study's efficacy estimate the researchers calculated that 18 (CI 6–22) pedestrian injury hospitalisations might be prevented in a year, were resources spent on traffic education instead used on traffic calmingThe extent of traffic calming was not detailed in relation to costs
The study did not account for the longer life time of traffic calming interventions compared with the one year cost