How abt system followed by Singapore to reduce congestion in roads?

The Land Transport Authority (LTA) in Singapore implemented an Electronic Road Pricing (ERP) scheme to deter traffic congestion during peak hours at various roads. The ERP scheme requires electronic gantries to be placed over the road at designated locations and that cars be equipped with an In-Vehicle Unit (IU), a rectangular device pasted on the inside bottom right of the front windscreen from the driver's view, which will deduct the toll price from aCashCard. The CashCard must be inserted into the device, and failure to do so is in violation of law. There is no charge for entering the area during certain non-peak times.