Background In 1948, Japan started a short-term publicity and enforcement campaign for traffic safety nationwide, and since 1952, the campaign has been conducted twice a year for 10 days. We aimed to quantify the short-term effect of the spring sessions of the campaign, which were conducted in different months in different years, on road fatalities in Japan using data from 1949 to 2019.
Methods We obtained national police data on the monthly number of road deaths and conducted a time series regression analysis with three steps: smoothing the long-term patterns with the natural cubic spline function, calculating the ratio of the monthly number of deaths to the corresponding smoothed value, and regressing the ratio on the number of months from January 1949 and the binary variable for the conduct of spring sessions. We repeated the analysis for four subperiods (1949–1964, 1965–1989, 1990–2004 and 2005–2019).
Results During the study period, there were 632577 road deaths. Our analysis revealed that the spring sessions changed the number of deaths per day by −2.5% (95% CI −4.1% to −0.9%) in the months when they were conducted. In the four subperiods, the estimated changes were −4.5% (95% CI −8.9% to −0.1%), −2.6% (95% CI −5.0% to −0.1%), −0.1% (95% CI −2.9 to 2.7) and −3.5% (95% CI −7.9 to 0.9).
Conclusions Road fatalities were reduced in the months when the spring sessions of the campaign were conducted, but the reduction was modest. The effect might have been somewhat larger until 1964, when Japan was a middle-income country.
- Wounds and injuries
- Health promotion
Data availability statement
Data are available on reasonable request. The data underlying this article will be shared on reasonable request to the corresponding author.
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Contributors MI conceived the study. HI designed the study. MI and HI obtained the data. HI analysed the data and drafted the manuscript. JT, SN and MI made comments that led to substantial revisions of the manuscript, and all authors approved of the final version. HI, being the corresponding author, attests that all listed authors meet authorship criteria and that no other individuals meeting authorship criteria have been omitted. HI accepts full responsibility for the work and/or the conduct of the study, had access to the data and controlled the decision to publish.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Disclaimer The views expressed in this article are our own and not an official position of the institutions.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.