The contracting authority wants to establish a dynamic purchasing system for the procurement and/or leasing of different cars. The contracting authority prefers the use of zero-emission cars to the greatest extent possible, as long as these cars can meet the needs of the contracting authority. The contracting authority shall therefore establish a dynamic purchasing system for the purchase and/or operational leasing of cars that mainly run on electricity or hydrogen. Some of the internal contests in the dynamic purchasing system can apply solely to cars with the above mentioned qualities. Where there is a lack of charging infrastructure and filling stations or if this type of cars does not meet the contracting authority's needs, fossil fuel cars can be requested.