For most trauma patients the initial life- and limb-saving care is achieved within the "golden hour". Prehospital treatment occupies most of the golden hour. More prehospital interventions were performed with HEMS than with EMS only, but the higher number of interventions did not result in a longer OST with HEMS. Although the numbers of subsequent in-hospital interventions may be lower, no reduction in time in hospital may be expected from the interventions performed before hospital admission.