road network outside the RZ. Because of heavier demand, only the Central Expressway required a separate licence, not valid for the RZ. During this time, a more modern system was being planned, to charge every time a user entered the RZ, and thus, charges would reflect the true cost of driving at congested times. Electronic Road Pricing (ERP) Overall, the ALS was successful in ensuring smooth traffic flow in the Central Business District. After about 10 years of planning and testing, in September 1998, the Area Licensing Scheme was terminated as Singapore upgraded to the current Electronic Road Pricing system, which is completely automatic and allows passing the control gantries at normal speeds. The ERP system is still in use in Singapore, and many similar schemes were based on it, such as the London congestion charge. See also Road pricing Electronic toll collection Edinburgh congestion charge Milan Area C Milan Ecopass New York congestion pricing San Francisco congestion pricing Stockholm congestion tax References Sources 1975 establishments in Singapore 1998 disestablishments in Singapore Area Road congestion charge schemes Area es:Peaje urbano de Singapur