Minimum Safe Time Gap (MSTG) as a new Safety Indicator incorporating Vehicle and Driver Factors

Safety of traffic operations on roads is of utmost importance especially in developing countries like Malaysia where the rate of motorization is still increasing. Apart from the common approach of conducting safety analysis based on historical data, simulation-based traffic safety analysis is becoming more common. This paper aims to propose a new safety indicator called the minimum safe time gap (MSTG) which incorporates vehicle dynamics and gross vehicle weight (GVW). This simulation-based safety indicator is able to analyze the capability of a vehicle in a car-following situation to safely stop without hitting the vehicle in front when an emergency brake is applied by considering the braking time of the two consecutive vehicles and the perception-reaction time of the driver of the following vehicle. Results from this simulation study indicate that the MSTG is influenced by the vehicle type and GVW, hence providing a more comprehensive safety indicator for safety analysis.