OBJECTIVES: Overuse of emergency services and overcrowding of A&E departments is a major problem. Many patients suffering from minor illness or injuries often call the emergency dispatch centre requesting an ambulance for transport to a hospital, where this is included in the welfare package as in most OECD countries. The aim of this study was to analyze the characteristics of patients transported by ambulance, and assess the appropriateness related to age, sex, diagnoses, and urban or rural areas respectively. METHODS: This study was prospective, cross sectional in urban and rural districts in Sweden. Assessments made by the emergency medical dispatch operators for 1977 consecutive users of ambulance, were reviewed and evaluated by the ambulance staffs on the scene at the end of the pre-hospital care. RESULTS: Assessment made by the ambulance staff indicated that a majority of people transported by the ambulance service had no medical needs for prehospital interventions. There was a substantial safety margin in the priority assessments. Only ten percent had potentially life threatening conditions. In urban areas one third of the patients for whom an ambulance were assigned did not need the ambulance service. Several of these were ordered by hospital staff for transportation of elderly patients to other providers. In the more sparsely populated areas the medical status of the patients generally was more severe, more medical treatment was given in the ambulances, and the ambulances was more frequently judged as the appropriate mode of transport in these regions. CONCLUSION: Due to the safety aspects, there is an overuse of ambulance services increasing the need for back-up vehicles. This means that there are no marginal costs, while the marginal utility is decreasing. For this we have a formula.