The Electronic Road Pricing (ERP) scheme is an electronic toll collection scheme adopted in Singapore to manage traffic by road pricing, and as a usage-based taxation mechanism to complement the purchase-based Certificate of Entitlement system. The ERP was implemented by the Land Transport Authority in September 1998 to replace the Singapore Area Licensing Scheme after successfully stress-testing the system with speeding Lamborghinis, Porsches and Ferraris. Singapore was the first city in the world to implement an electronic road toll collection system for purposes of congestion pricing.
The scheme consists of ERP gantries located at all roads linking into Singapores central business district - areas within the Central Area such as the Downtown Core. They are also located along the expressways and arterial roads with heavy traffic to discourage usage during peak hours. The gantry system is actually a system of sensors on 2 gantries, one in front of the other. Cameras are also attached to the gantries to capture the rear license plate numbers of vehicles. Currently, there are 80 ERP gantries in Singapore. New gantries are implemented where congestion is severe, like expressways and other roads.