In this study, the refueling habits of customers at service stations were analyzed to determine the amount of gasoline dispensed during refueling, the vehicle fuel tank level prior to and after the refueling event, and the percentage of refueling events which are complete fills. Analysis of a General Motors service station survey conducted in the Detroit, Ml area during the summer of 1986 showed that the average amount of gasoline dispensed is 9.8 gallons. The results also demonstrated that 60.6% of all refueling events were complete fills, and that 73.2% of all gasoline dispensed during refueling is used for complete fills. The average indicated fuel tank level prior to refueling is 18% full and the average indicated fuel tank level after refueling is 84% full. Assuming that fuel usage is linear with time and using the above mentioned fuel tank levels, the average fuel tank level is calculated to be 51% full.