Fleet Fatality Risk and its Sensitivity to Vehicle Mass Change in Frontal Vehicle-to-Vehicle Crashes, Using a...

Area of Science:

• Traffic Safety
• Vehicle Dynamics
• Risk Analysis

Background:

• Vehicle mass significantly influences crash outcomes.
• Current vehicle fleets exhibit a wide range of masses.
• Understanding mass-related fatality risk is crucial for safety improvements.

Purpose of the Study:

• To analytically model fatality risk in frontal vehicle-to-vehicle crashes.
• To assess the sensitivity of this risk to changes in vehicle mass.
• To determine the societal mean fatality risk across a distribution of vehicle masses.

Main Methods:

• Developed a model using empirical risk-mass ratio and theoretical momentum conservation.
• Averaged individual vehicle risks over closing velocity distributions.
• Calculated societal mean fatality risk by averaging over all crash partners.

Main Results:

• Decreasing subject vehicle mass increases its fatality risk while decreasing partner risk.
• Societal mean fatality risk is minimized near fleet mean mass, incurring penalties for mass inequality.
• Overall fleet mean fatality risk increases linearly with decreasing average vehicle mass (approx. 0.8% per 100 lb decrease).

Conclusions:

• Vehicle mass disparity significantly impacts societal crash fatality risk.
• Fleet-wide mass reduction increases overall fatality risk.
• Safety interventions should consider the impact of mass distribution on crash outcomes.