Which driving speed is associated with optimal gas mileage?

Driving at 55 mph is widely recognized as the speed that maximizes fuel efficiency for most vehicles. This is due to a combination of factors, primarily involving aerodynamic drag and engine performance. At higher speeds, vehicles experience increased wind resistance, which requires more energy and, consequently, more fuel. In contrast, at lower speeds, while fuel consumption may also be lower, it often does not optimize the engine's efficiency.

Studies have shown that many cars reach an optimal point around 55 mph, where the engine operates in its most efficient range, balancing acceleration needs and fuel usage. Driving beyond this threshold, such as at 65 mph or 75 mph, often leads to a significant drop in gas mileage. Hence, maintaining a speed of 55 mph not only keeps fuel consumption more economical but also contributes to less pollution and lower overall travel costs.