Should You Turn Off the Engine at a Red Light?
2 Answers
It is not recommended to turn off the engine while waiting at a red light, as this practice does not save fuel. The duration is relatively short, and the fuel injected during restart is roughly equivalent to the fuel consumed during idling. Additionally, it can wear out the starter and shorten the battery's lifespan. Relevant information is as follows: 1. Consider the duration of the stop before turning off the engine. If the stop lasts longer than 2 minutes, it is acceptable to turn off the engine. For shorter stops, there is no need to do so. The engine, being the heart of the vehicle, will suffer reduced lifespan from excessive shutdowns and restarts. Frequent ignition starts also affect the lifespan of the spark plugs. 2. Traffic congestion should be evaluated based on duration. If the idle time is expected to be prolonged, such as during traffic control, it is advisable to turn off the engine. For short-term congestion (e.g., waiting at a red light), it is not recommended to turn off the engine.
Having driven for over a decade, I believe this issue should be considered case by case. Turning off the engine at short red lights in urban areas simply isn't worth it - the fuel consumed during engine restart is greater, plus it increases starter wear. I once tested this on an older model car, finding each start-stop cycle consumed 0.7ml more fuel than idling. Calculating 20 traffic lights daily, you'd only save half a tank annually. For prolonged traffic jams or railroad crossings with 3+ minute red lights, engine shutoff makes sense - but always observe traffic signals in advance to avoid frantic restarts when lights turn green, which might prompt honking from behind. Older vehicles especially shouldn't undergo frequent shutdowns, as their batteries and starters can't withstand constant cycling.
