An experimental investigation on the requirement of roof height and sill width for car ingress and egress

Ergonomics. 2012;55(12):1596-611. doi: 10.1080/00140139.2012.722694. Epub 2012 Sep 25.


This study aimed at experimentally investigating the influence of roof height and sill width on car ingress/egress movements. The first uncomfortable (Ht1) and the lowest acceptable (Ht2) roof heights were obtained from 26 participants of three different stature groups thanks to a multi-adjustable vehicle mock-up. Both Ht1 and Ht2 were affected neither by stature nor by vehicle type. Only a difference of 45 mm between Ht1 and Ht2 was observed. Tall volunteers more flexed the trunk and neck than short persons thanks to a larger space available around the seat when the head passing under the roof. The vehicle type had almost no effect on upper body posture. The roof height only affected neck flexion. The sill width mainly imposed a lateral translation. Results demonstrated that an appropriate roof height should be determined carefully. A small change of 45 mm in roof height may lead to an unacceptable situation.

Practitioner summary: The present study experimentally investigated the effects of roof height and sill width on car ingress and egress movements. Short females required almost the same roof height as tall males due to smaller space around the seat. The results would help to optimise car dimensions for improving car accessibility.

MeSH terms

  • Adult
  • Automobiles*
  • Body Height
  • Equipment Design
  • Ergonomics*
  • Female
  • Humans
  • Male
  • Movement*
  • Young Adult