Are deceleration numbers a suitable index for road safety?

The accessibility of advanced technology now provides an opportunity for researchers to resolve road safety problems by analysing violent manoeuvres of vehicles as a surrogate measurement. This study investigated the possibility that the numbers of deceleration records of sample vehicles (deceleration numbers) could be used as a surrogate measurement for crash data in road safety analyses. To this end, deceleration numbers at different intensities were obtained through real-time data (at 1 s intervals) from smartphone sensors. The correlation between deceleration numbers (at different intensities) was then examined based on valid safety parameters (crash rate, crash frequency, crashes involving fatality or injury and damage-only crashes). The results demonstrated a substantial correlation between the empirical Bayesian parameter and deceleration numbers. The Spearman correlation coefficient between the two parameters was 0·794 (at a very high significance level), which is notable from a statistical perspective.