Abstract
The aim of this investigation is to study the pulse frequency changes of sixty drivers during skidding. Thirty inexperienced drivers (students) and thirty experienced drivers (police-man) were driving for 40 min. each in a passenger car adjusted in a manner by which the rear axle could be steered separately, thus causing the car to skid. In both groups the pulse frequency rose significantly during driving without skidding. On account of the unexpected skid the pulse frequency increased still more. Inexperienced drivers remained under stress for a considerable time.