New Method for Distance-based Close Following Safety Indicator

<b>Objective:</b> The increase in number of fatalities caused by road accidents involving heavy vehicles every year has raised the level of concern and awareness on road safety in developing countries like Malaysia. Changes in the vehicle dynamics’ characteristics such as gross vehicle weight, travel speed and vehicle classification will affect a heavy vehicle's braking performance and its ability to stop safely in emergency situations. As such, the aim of this study is to establish a more realistic new distance-based safety indicator called the minimum safe distance gap (MSDG) which incorporates vehicle classification (VC), speed and gross vehicle weight (GVW).<b>Method:</b> Commercial multi-body dynamics simulation software was used to generate braking distance data for various heavy vehicle classes under various loads and speeds.<b>Results:</b> By applying non-linear regression analysis to the simulation results, a mathematical expression of MSDG has been established. The results show that MSDG is dynamically changed according to GVW, VC as well as speed.<b>Conclusions:</b> It is envisaged that this new distance-based safety indicator would provide a more realistic depiction of the real traffic situation for safety analysis.