The Effect of Bumper Dimensions and Car Speed on Neck and Lower Back Forces

: Vehicle vibrations significantly affect the health and comfort of the driver and passengers. The aim of this study is to analyze the effects of vertical vehicle vibrations caused by speed bumpers on the driver's lower back and neck in terms of forces. To achieve this goal, a human biodynamic model with 11 degrees of freedom was included in a half vehicle model with 5 degrees of freedom. This composite human vehicle model was subjected to half-sinusoidal shaped bumps of different sizes (heights and widths) and with different vehicle speeds. The equations of motion of the system were solved using MATLAB (R2021a) to find the forces acting on the lower back and neck joint. In this article, besides commenting on the speed of the cars passing through the bumps, the effect of the bumps on the driver's lower back and neck was tried to be deduced in terms of forces. The results are presented visually and comparatively in graphs. At the end of the article, it was concluded that the mentioned speed bumps should be designed considering human comfort and health. In addition, in biomechanical studies examining human-vehicle-road interaction, it was emphasized that the parameter values of the human body should be determined more realistically.