To deter such behavior, toll operators can employ tools such as high-definition cameras to identify violators, and leakage can be offset in part or whole by fees and fines collected against offenders.
However, in many cases such enforcement is relatively limited (for example, targeting only commercial vehicles and other such flagrant and/or repeat offenders).
[citation needed] In 1959, Nobel Economics Prize winner William Vickrey was the first to propose a system of electronic tolling for the Washington metropolitan area.
[5] In September 1998, Singapore became the first city in the world to implement an electronic road toll collection system for purposes of congestion pricing.
[6] Today there are many roads around the world using electronic toll collection technologies, and ORT has opened the feasibility to implement congestion pricing policies in urban areas.
Some early systems used barcodes affixed to each vehicle, to be read optically at the toll booth.
Optical systems proved to have poor reading reliability, especially when faced with inclement weather and dirty vehicles.
ANPR allows police to automatically compile vast databases of innocent road users' movements, thus invading their privacy.