S/S on a car's dashboard or button typically stands for the "Stop-Start System," an engine management feature designed to improve fuel efficiency and reduce emissions. When you come to a complete stop, like at a traffic light, the system automatically shuts off the engine. The moment you lift your foot off the brake pedal, it restarts the engine almost instantly. This technology is most common in hybrid vehicles but is also found in many modern gasoline-powered cars.
The primary benefit is fuel savings, especially in city driving with frequent stops. By eliminating idling, the system reduces fuel consumption and tailpipe emissions. The system is smart; it won't activate if the engine is too cold, the battery charge is low, or the air conditioning is working hard to maintain a set temperature.
You'll often find a button labeled "A" with a circular arrow, sometimes accompanied by "S/S" or "Off," which allows you to disable the system. Some drivers prefer to turn it off for very short stops or when maneuvering in parking lots, as the engine restart can feel abrupt. However, for most daily commutes, leaving it on is the most efficient choice.
| Supporting Data: Stop-Start System Effectiveness | |
|---|
| Fuel Economy Improvement | Up to 3-10% in city driving conditions (EPA) |
| Reduction in CO2 Emissions | Approximately 5-7% in urban traffic (Society of Automotive Engineers) |
| System Activation Threshold | Typically requires a complete stop for 1-2 seconds |
| Average Number of Starts/Stops | Can perform over 100,000 start cycles in a vehicle's lifetime (Consumer Reports) |
| Battery Specification | Uses an enhanced Absorbent Glass Mat (AGM) battery to handle frequent cycling |
