Complex sentence: In London, the Oyster card payment system can track the movement of individual people through the public transport system, although an anonymous option is available, while the London congestion charge uses computer imaging to track car number plates.
Split into simpler sentences: In London, the Oyster card payment system can track the movement of individual people through the public transport system, although an anonymous option is available. The London congestion charge uses computer imaging to track car number plates.