The effect of police density to improve motorcycle helmet use in Thailand

While it is well established that motorcycle helmets reduce the risk of fatal injury and death, scaling up law enforcement on helmet use is still a big challenge for developing countries. These countries have a heavy burden from motorcycle-related injuries, but have limited resources for law enforcement. This report used cubic spline regression analysis on national datasets and a nationwide roadside survey of helmet use in Thailand. It has demonstrated that police density (number of policemen per square kilometer) is an independent predictor of helmet use (p<0.001) after controlling for adult literacy. This finding is consistent with evidence about effective deployment of limited numbers of police to ensure substantial and sustainable reductions of fatal road crashes in the rural road network in Queensland State of Australia. Concerning policy decisions about resource allocation, the finding provides a new parameter for allocation of limited numbers of police. Police density was also significantly associated with gross provincial product (GPP) per capita (p<0.001) and population density (p < 0.001). These additional important findings raise concerns about equitable allocation of the police force in Thailand.