Should I use S gear or D gear on the highway?
2 Answers
Cars can use D gear on the highway; D gear is the drive forward gear, and as long as it's normal road conditions, such as long downhill slopes or high-speed driving, there are no issues; because D gear does not use the automatic transmission, it is less restrictive to use; once D gear is engaged, the transmission will automatically adjust the speed. Introduction to car S gear: S gear can be used while driving, especially when overtaking. Sometimes, if the accelerator pedal is not pressed immediately, the car's power may not come out promptly. If you switch to S gear at this time, it can quickly increase speed, especially during high-speed overtaking; S gear needs to be used appropriately because prolonged use of S gear can cause the car's engine to be overloaded, reducing the engine's lifespan. Introduction to car D gear To better ensure the automatic car's engine cruises at lower RPMs, D gear is more suitable; because D gear is based on the automatic transmission's strategy enhancement principle, D gear adjusts the gear according to driving conditions, speed control will be smoother, and the car's RPM will also be relatively lower; D gear's speed adjustment cannot obtain higher power, and it is more fuel-efficient compared to S gear.
Having driven for over 20 years, using D mode is definitely more worry-free for most highway driving. The S sport mode delays gear shifts and keeps the RPM high, which is suitable for quick power boosts when overtaking. But cruising at high speeds in S mode for extended periods makes the engine roar loudly and significantly increases fuel consumption – the dashboard fuel economy reading can jump by 30%. My old Accord is a perfect example: it gets 6L/100km in D mode during steady highway driving, but that figure spikes to 8L/100km in S mode. Unless you're tackling continuous uphill/downhill sections or want an aggressive overtaking burst, there's really no need to bother. Regular automatic transmissions are smooth enough in D mode – even those 8-speed or 10-speed gearboxes respond quickly when left in D.
