Furthermore, two recent technological advancements have made congestion pricing schemes both affordable and
administratively feasible. The first is electronic road pricing of the type currently used in many states as a part of
their tolling schemes. 57 Drivers purchase accounts with the state or road operator and receive a transponder which
is placed on the dashboard of the vehicle. When the commuter enters a road or area subject to congestion pricing the
transponder signals a sensor, and a deduction in the amount of the toll is automatically made from the user's account.
The second option is to use “cash cards,” an approach currently used in Singapore's congestion pricing system. 58 Such
cards work much like telephone cards and can be bought or recharged at retail outlets, banks, gas stations, and automatic
machines. 59 The driver can place funds onto the card and then fix it to a vehicle's windshield. 60 As with the transponder
system, once the commuter passes onto a road subject to user charges, the card signals a sensor and a deduction in the
amount of the toll is made from the card. 61 In addition, technological advancements have also made enforcement more
effective. As with toll systems throughout the country, surveillance cameras can be used to photograph the license plates
of violators or those who do not have adequate funds to account for the toll. Tickets with appropriate penalty charges
can then be sent to those drivers.