In case of public transportation, the protection of the environment and the economic operation are highlighted issues. The cold start and the cold operational procedure of buses must be optimal both in the scope of environment protection and economic aspects (fuel consumption, wear and tear). By taking these factors into consideration, we have analysed the relevant influential factors and elaborated such a measuring system with the aid of which the fuel consumption can be measured continuously during the operation. Fuel consumption measurements were accomplished with the aid of a new measuring system during cold operation and running and on the basis of processing and evaluating the findings we have suggested a new operational procedure.