The letter from Dr Bruce Paix (see http://dx.doi.org/10.1111/j.1742-6723.2006.00861.x) about relative road safety for holiday periods may be subject to selection bias. He has used the daily average road toll as the benchmark to compare with an abnormal period of time, which includes public holidays. Easter, measured over 5 days, contains two public holidays, and the 15-day Christmas break contains three public holidays. The other 345 days of the year contain four to five public holidays, depending on the state. Traffic volume is much reduced on public holidays, as fewer people are at work, schools are closed, and peak (rush) hours are nonexistent. The entire Christmas period is one of lower traffic volume, as businesses close and many people take holidays. Consequently, the very modest reduction in deaths, he calculates (2% at Christmas, 7% at Easter), may even represent an increased mortality per vehicle passenger mile travelled. Alternatively, this lower death rate may be a sign of campaign success! However, better evidence is needed before extant road trauma preventive strategies are abandoned. (Author/publisher)
Samenvatting