The first road pricing scheme, known as the Area Licensing Scheme (ALS), is introduced.
This scheme covers the more congested parts of the Central Business District, designated as the Restricted Zone.
Cars with three or more passengers, excluding the driver, are exempted.
Motorists must buy a paper licence at $3 a day, before passing through control points on the roads, monitored by enforcement personnel.
Operations hours are from 7.30am to 9.30am daily, except Sundays and public holidays. It is later extended to 10.15am.
JUNE 1989
The scheme is extended to evening peak hours, from 4.30pm to 7pm on weekdays, following rapid growth in vehicle population.
January 1994
Restricted hours are further extended to 10.15am to 4.30pm on weekdays and 10.15am to 3pm (later to 2pm) on Saturdays. Car pools are abolished because private cars are picking up bus commuters.
SEPTEMBER 1998
Electronic Road Pricing (ERP) system replaces the manual ALS, starting with 33 gantries.
SEPTEMBER 1999
ERP is extended to some key roads beyond the Restricted Zone.
AUGUST 2005
Evening ERP kicks in on the Central Expressway. In the Orchard Road area, more gantries are introduced and operation hours are extended to 8pm on weekdays, and on Saturdays, from noon to 8pm, to control traffic flow in and out of the shopping belt.
JANUARY 2008
Announcement of fundamental changes to ERP system.