Spark plugs are a necessary component of the internal combustion engine, which is found in the majority of traditional gasoline-powered vehicles. Spark plugs generate an electric spark that ignites the fuel in the engine's cylinder, causing the engine to start.

If the internal combustion engine is phased out, spark plugs will most likely no longer be used in vehicles. However, it is difficult to predict how the transportation landscape will evolve in the future, and spark plugs may continue to be used in some capacity even if internal combustion engines become less common.