Can we persuade children to wear cycle helmets? Does installing cameras at road junctions with traffic signals reduce crash rates? Does the “safe community” scheme endorsed by WHO actually work? These are typical instances of where interventions to reduce injury “make sense”; however, a thorough evaluation of their use is required to determine whether they actually deliver the goods. Authors working with the Cochrane Injuries Group (CIG) have therefore recently undertaken systematic reviews that address these three questions.

“Red light cameras” are widely used in many countries to identify drivers that jump (“run”) red lights, who can then be prosecuted. The CIG review¹ looked for controlled studies of their effectiveness in reducing the number of times that drivers drive through red lights and the number of crashes. Very little research has been done and much of it has not allowed for statistical problems, such as regression to the mean and “spillover” effects—that is, changes in crash rates at nearby junctions where no cameras were installed. However, five studies in Australia, Singapore, and the USA all found that red light cameras cut the number of crashes in which there were injuries. In the best conducted of these studies, the reduction was nearly 30%. More research is needed to determine best practice for red light camera programs, including how camera sites are selected, signing policies, publicity programs, and penalties.

An earlier CIG review² concluded that wearing a helmet reduced bicycle related head and facial injuries for bicyclists of all ages, in all types of crashes. A new review³ focused on encouraging children to wear helmets, as distinct from compelling them to do so through laws. The authors aimed to find out which sort of campaigns work best, particularly with children from poor families. They found 22 helmet promotion campaigns that had been studied. Campaigns varied with regard to where they were carried out, age of the children, campaign methods, and so on. Results also varied but overall, after a campaign, children were more likely to wear helmets. More research is needed but it seems that the best schemes are based in the community and involve both education and providing free, or possibly subsidised, helmets. Helmet promotion in schools also seems to be effective. The reviewers could not identify the best way of reaching poorer children. The studies included did not look at the impact on injury rates, or assess whether promotion campaigns had any negative effects.

Eighty communities across the world have been officially designated as WHO Safe Communities. CIG reviewers⁴ looked for evidence as to whether they really have reduced injury rates. Only seven (five in Scandinavia and one each in Australia and New Zealand) have collected information in a reliable manner. The overall results of the review were positive, although the Scandinavian communities seem to have been more successful than the others. More research of good quality is needed. No research has been done on WHO Safe Communities located in poorer countries.