You get the best gas mileage when?

• A. At the highest speed
• B. The slowest speed of your highest gear (normally around 45-50 mph)
• C. Idling in traffic
• D. Moderate speed in middle gear

Answer: (B)

The best gas mileage comes when the engine is running at a low number of revolutions while you’re still moving, which means using the highest gear that can comfortably maintain the speed. In many cars, that happens around forty-five to fifty miles per hour. At this pace the engine isn’t working too hard (low RPM) but you’re still moving, so you get more miles per gallon.

Raising speed dramatically increases air resistance, so pushing to higher speeds wastes fuel even though you cover distance faster. Idling in traffic wastes fuel without any distance gained. In a middle gear at moderate speed, the engine RPM is higher than in top gear, so fuel use per mile isn’t as low as it is in the highest gear at a steady, moderate speed.