This project is a collaboration between Toyota's CSRC and University of Michigan Transportation Research Institute

Senior drivers and passengers are much more vulnerable to injuries in car crashes than are younger occupants. Analyses of crash data have demonstrated that most of the increased risk is due to reduced injury tolerance (fragility) rather than the reduced ability to recover from injury (frailty).

Efforts to improve crash outcomes for senior occupants are limited by the lack of data on the ways in which they differ from younger occupants. Previous studies have focused on the thoracic skeleton, documenting changes in rib and bone composition that lead to reduced tolerance to external forces.


Other changes associated with age may also influence restraint system performance and injury outcomes. For example, the distribution of abdominal fat in older occupants may result in belt fit differences that reduce belt effectiveness and increase injury risk. Older drivers may also sit more upright or further forward than younger drivers with the same stature and body weight, which may affect their kinematics and injury risk during an impact event.

Toyota’s CSRC and UMTRI are working together to develop quantitative statistical models of the effects of age on driver and passenger posture, body shape, and belt fit.

The CSRC and UMTRI will explore three main research questions relating to how older occupants interact with the vehicle:

(1) Do senior drivers and passengers sit differently from younger passengers?
(2) Are body shapes of older and younger occupants different at the same stature and body weight?
(3) Do senior occupants experience different belt fit in driving posture?

The study will target volunteers of different age groups with BMI (Body Mass Index) distribution representative of the American population. For each volunteer key landmarks on the individual seated in comfortable driver & passenger positions will be measured, as well as the volunteer’s choice of seat location relative to the foot pedals & steering wheel, seat-back angle, and seat belt routing location. The test subjects’ exterior body shape will also be recorded in various seating postures to collect information on body shape changes with age. The data will be used to create statistical models representing driver and passenger posture, body shape, and belt fit changes with age.


This 18-month project initially begins with construction of the test vehicle environment. Subject recruitment will begin after the third month, and continue for 1 year. The final six months of the project will be spent analyzing the data and creating models to quantify the age effect on the three areas: posture, body-shape, and belt-fit.