What is the most fuel-efficient speed on the highway?

[ElianaDella]

Driving at 80-100 km/h on the highway is the most fuel-efficient. The economical speed for sedans is around 80 km per hour. When the speed increases to 105 km per hour, fuel consumption will increase by 15%, and at 120 km per hour, it will increase by 25%. Factors affecting fuel consumption: 1. Gear and RPM: Generally, automatic transmission vehicles are designed to cruise at around 1500 RPM for fuel efficiency. Even at the same speed of 100 km/h on the highway, driving in 4th gear at 3000 RPM, 5th gear at 2000 RPM, or 6th gear at 1500 RPM will result in completely different fuel consumption levels. 2. Regular maintenance: It is advisable to pay attention to regular vehicle maintenance, especially the tire system and air filter, which are crucial for saving fuel. If tire pressure is insufficient, even by just 1 PSI, it can reduce fuel economy, while over-inflation can also lead to increased fuel consumption. 3. Driving habits: Gentle acceleration, less braking, using the correct gear, avoiding frequent gear changes, and making reasonable judgments about road conditions. Keep your eyes on the road ahead and frequently check the rearview mirror to anticipate the surrounding traffic conditions, vehicle flow, and the driving paths of nearby vehicles. This approach helps drivers rely more on coasting in gear and maintaining a reasonable safe distance from the vehicle ahead to achieve fuel-saving effects.

[StNevaeh]

I've been driving on highways for many years and found that the most fuel-efficient speed is usually between 80 to 100 kilometers per hour. Driving too fast causes a sharp increase in wind resistance, requiring heavy throttle input; driving too slow reduces engine efficiency and actually consumes more fuel. When I maintain my regular sedan at around 90 km/h, the fuel consumption is approximately 5.5L/100km; if I accelerate to 120 km/h, the fuel consumption can exceed 7L. This doesn’t even account for windy days or the impact of wind resistance on SUVs, where taller vehicles are more affected by wind speed. Routine maintenance like proper tire pressure, avoiding sudden braking, and using cruise control helps a lot. Once, driving from Beijing to Tianjin, I maintained a steady speed of 95 km/h and saved 30 yuan in fuel costs while also reducing wear and tear. After making it a habit, I now drive this way every time I’m on the highway.