Identifying the Relationship Between Occupant Injuries and Vehicle Mass; An Innovative Approach to Maximising Crashworthiness Efficiency and Inter-Category Compatibility

  • Andrew Harrison

Student thesis: Doctoral ThesisDoctor of Philosophy


To achieve Vision Zero, road safety is at the forefront of concern, especially considering the development of new vehicle designs and application of Advanced Driving Assistance Systems (ADAS). Despite the effectiveness of ADAS in reducing the quantity and severity of rear-end crashes, high risk scenarios are likely to remain within urban environments until fully connected vehicle and city infrastructure is established. The market share projection is divided between larger passenger vehicles (M1) and lightweight microcars (L7e) for future transport hubs and the ‘next generation’ of mobility. The differences between the structural designs and masses of the vehicle, in relation to occupant safety, are of great concern as the smaller vehicle is at 10-times
the risk of sustaining injuries.

The research conducted throughout this thesistook an analytical approach to examine and explore the effects of vehicle masses and vehicle mass-ratios to combat the upcoming crash compatibility issues. The first study examined the relationship between vehicle mass-ratios and occupant injury. Measures were taken to manage the influence of other compatibility factors. The results of the first study were indicative of a relationship
between vehicle mass-ratio and occupant injuries sustained and showed that occupant injury metrics likely begin to plateau at a bullet vehicle to target vehicle mass ratio of 3:1, reaching the maximum by 4:1. This study identified a pre-liminary relationship between the masses of bullet (M1) vehicle and the injury metrics of the L7e occupant, which was then used to define a ‘favourable’ vehicle mass ratio for the benefit of the L7e occupant.

A novel method of light-weighting with respect to occupant injuries was developed. The mass reduction procedure adopted a unique approach to crash safety and crashworthiness efficiency by prioritising and ranking vehicle components by segment location, thickness, and material selection in relation to occupant
positioning with respect to high-risk scenarios. The partnered approach objectively reduced vehicle mass whilst increasing vehicle-to-vehicle compatibility for a lateral impact. The unique method adopted provided results that highlight the feasibility of increasing compatibility by a function of vehicle mass and improvement to more practical placement and focus of protective structures.

Date of Award2022
Original languageEnglish
Awarding Institution
  • Coventry University
SupervisorJesper Christensen (Supervisor), Christophe Bastien (Supervisor) & Alexis Wilson (Supervisor)

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