Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Automotive Engineering

Committee Member

Paul J. Th. Venhovens, PhD, Co-Committee Chair

Committee Member

Johnell O. Brooks, PhD, Co-Committee Chair

Committee Member

John D. DesJardins PhD

Committee Member

Kevin Kopera, MD, MPH

Committee Member

Patrick J. Rosopa PhD


The objective of this research was to measure and understand the preferred seat position and posture of older drivers and younger drivers within their personal vehicles to influence recommended practices for meeting the safety needs of all drivers.Currently, the United States is experiencing an ageing population, whereby in 2020 nearly 40 million people over the age of 65 will be licensed drivers. In addition, crash reports show that older drivers are over represented in vehicle fatality statistics, once adjusted for vehicle miles traveled. The increased fatality rate of older drivers has been attributed to a combination of increased fragility of older drivers and their selected seat position. Educational programs, such as CarFit©, have been established to teach older drivers about safe seating guidelines in an effort to reduce the over representation of older drivers in crash statistics.

The research for this dissertation was conducted to collect data from older drivers over the age of 60 and younger drivers between the ages of 30 to 39. Data were collected within the driver’s personal vehicle to obtain a natural and accurate driver selected seat position. Each driver was measured twice. The first set measures were obtained right after the driver’s arrival to the study site in the seat position the driver had selected. The second set of measures were taken after each driver was educated on CarFit© safe seating guidelines.

The results of this dissertation show that the addition of an age term to the SAE J4004 recommended practice model for predicting driver selected seat position of any driver is a statistically significant contribution to the model thereby, improving the fit of the model and the accuracy of the predicted seat position model. In addition, age was shown as predictor variable for the CarFit© line of sight above the steering wheel measure, whereby older drivers were 5 times more likely than younger drivers to meet the CarFit© guideline of a 76 mm (3 in) line of sight above the steering wheel. Last, stature was shown as a predictor variable for the likelihood of meeting the CarFit© criteria, where tall-statured individuals were less likely to meet the backset, top of head to ceiling, and top of leg to bottom of steering wheel measurements and more likely to meet the line of sight above the steering wheel measurement.



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