What is the difference in fuel consumption between national roads and highways?

[VonTravis]

The fuel consumption difference between national roads and highways is approximately 2 liters. Possible reasons for higher fuel consumption include unnecessary increase in vehicle load, frequent braking and acceleration, and driving at high speeds in low gears. Unnecessary increase in vehicle load: Many new car owners tend to load their vehicles with various decorations and exterior accessories, and some even go as far as moving their office and home into the car. Blindly installing body kits, spoilers, winches, and roof racks can also increase the vehicle's fuel consumption. Frequent braking and acceleration: Apart from vehicle design and engine factors, the main cause of wasted fuel is the driver's habits. Frequent hard braking and rapid acceleration are the biggest contributors to increased fuel consumption. An experiment once showed that the same car driven by different drivers resulted in the novice driver consuming twice as much fuel as the experienced driver. This demonstrates how important good driving habits are for saving fuel.

[ChristianLee]

My car often goes on long-distance trips, and the fuel consumption difference between national roads and highways is quite noticeable. Driving on national roads with frequent traffic lights, constant starts and stops, and lower speeds leads to significantly higher fuel consumption. My 1.5T engine consumes around 8 liters per 100km on national roads. On highways, it's much more fuel-efficient. Maintaining a steady cruise speed of 100km/h keeps the RPM at around 2000 with lower air resistance, bringing fuel consumption down to under 6 liters per 100km. However, if you push beyond 120km/h on highways, fuel consumption actually increases due to the exponential growth of air resistance. I think the best way to save fuel is to take highways and control your speed - national roads waste both fuel and energy.

[MaddoxLee]

I've been driving for ten years, and I believe fuel consumption differences mainly depend on road conditions. On national highways, you have to slow down for various unexpected situations, with more pedestrians and intersections, averaging 40 km/h, fuel consumption is at least 1.5 liters higher than on highways. Last time I tested with a company car, for the same 100-kilometer distance, the highway only burned 7 liters of fuel, while the national highway surprisingly reached 9 liters. However, it's important to note the differences in vehicle types. SUVs have higher wind resistance, and at 120 km/h on the highway, fuel consumption might even surpass that on national highways. I recommend choosing highways for long-distance trips to save fuel and time; national highways are more suitable for short, unhurried journeys.

[EmersynMarie]

Simply put, driving on national highways consumes more fuel. Frequent traffic lights and constant acceleration and braking are particularly fuel-intensive, with the engine often operating in inefficient ranges—similar to constantly restarting a computer, which is very power-hungry. In contrast, steady-speed driving on highways is much more energy-efficient, with most vehicles achieving optimal fuel economy at 80-100 km/h. How big is the difference? Based on my experience, the same car can see a difference of 2-3 liters per 100 kilometers. If you frequently drive on national highways, consider using ECO mode to reduce fuel consumption.