On average, it takes approximately 5 to 10 minutes to fill a car's fuel tank at the same spot. This duration can vary depending on several factors, including the size of the fuel tank, the flow rate of the pump, and the speed at which the driver operates the pump.

The time it takes to fill a car's fuel tank is influenced by the capacity of the tank. Smaller tanks, typically found in compact cars, can be filled in about 5 minutes, while larger tanks, often found in SUVs and trucks, may take closer to 10 minutes. The flow rate of the pump also plays a significant role; modern fuel pumps are designed to deliver fuel at a consistent rate, but older models may have slower flow rates. Additionally, the driver's pumping speed can affect the overall time; a slower pumping speed will naturally extend the filling time.

According to a study by the National Renewable Energy Laboratory (NREL), the average fueling time for a passenger vehicle in the United States is approximately 7 minutes. This study also found that the average fueling rate is about 3.5 gallons per minute, which aligns with the typical flow rates of modern fuel pumps. The NREL's research indicates that the variability in fueling times is primarily due to the size of the fuel tank and the driver's pumping speed.

In conclusion, the average time to fill a car's fuel tank at the same spot is around 5 to 10 minutes, influenced by factors such as tank size, pump flow rate, and driver operation. The National Renewable Energy Laboratory's data supports this range, highlighting the importance of these factors in determining fueling time.