Can an Automatic Transmission Car Coast in Neutral?
2 Answers
An automatic transmission car should not coast in neutral while driving. The reasons are as follows: 1. When an automatic transmission car is coasting in neutral, the braking force of the vehicle decreases, which can easily lead to rear-end collisions. This is because, in neutral, the connection between the engine and the drive wheels is lost, and the car moves forward solely by inertia. In an emergency requiring braking, all braking force must be provided by the brakes alone. In contrast, when coasting in gear, the engine itself provides some resistance, and combined with the brakes, the braking distance is shortened. Additionally, coasting in neutral can cause the engine to stall, leading to failure of the brake booster and reduced braking performance. 2. Coasting in neutral does not save fuel and can sometimes even consume more fuel, which is related to the working mechanism of electronic fuel injection engines. According to engine principles, electronic fuel injection engines can determine the amount of fuel injection based on computer programs. When coasting in gear, if the driver releases the accelerator, the computer will put the car into coasting mode, during which the engine does not inject fuel for a long period. However, if neutral coasting is selected, the computer will put the car into idle mode, and the engine continues to inject fuel. This is why coasting in neutral can sometimes consume more fuel.
Let me share from the perspective of an experienced driver. I remember one time when I tried to save effort by coasting in neutral on the highway. When I hit the brakes, they felt stiff, and I almost rear-ended the car in front. That’s because engine braking disappears in neutral, leaving the entire burden on the brake system. But the increased load on the brakes makes them prone to overheating and failure, especially downhill, where the car can accelerate uncontrollably. Later, I asked a mechanic, and he said that in automatic transmissions, coasting in neutral reduces oil pump speed, leading to insufficient lubrication. Over time, this causes component wear, costing thousands in repairs—hardly worth the tiny fuel savings. Modern cars have smarter, more fuel-efficient coasting functions in Drive (D). Since then, I’ve only driven in D, forming a much safer habit—never gamble with safety for minor conveniences. This lesson reminded me that driving isn’t just about ease but also risk awareness, and anticipating road conditions is the best strategy.
