Electronic road pricing (Hong Kong)

Electronic road pricing (ERP, Chinese: 電子道路收費系統) is an electronic toll collection scheme first proposed in Hong Kong as early as in the 1980s to manage traffic by congestion pricing. (Singapore, which first adopted ERP in 1998, was the first city in the world to implement electronic congestion pricing.) Hong Kong first conducted a pilot test on the electronic road pricing system between 1983 and 1985 with positive results, but when it tried to implement an actual electronic road pricing, it failed because of public opposition.

Source: Wikipedia — Electronic road pricing (Hong Kong) (CC BY-SA 4.0)