the gantries, but their number plates were taken down and their owner would receive an order to appear in court to pay the fine. The control was made only at the gantries, therefore, vehicles were free to move around or leave the RZ without having to pay the fee. ALS gantries were enforced by CISCO officers, who manually screened passing vehicles and book offending vehicles with fines. Prior to the end of the ALS and the beginning of Electronic Road Pricing (which rendered manual checks obsolete), 105 such officers were deployed. Impact According to the book The Journey – Singapore's Land Transport Story, the amount of traffic entering the Restricted Zone in June 1975 (before the ALS was introduced) was 32,500 vehicles, and after the beginning of the ALS in June 1975, the vehicle numbers dropped to only 7,700, between the hours of 7.30 am to 9.30 am, a 76% reduction; and 9% of the users switched to transit. The use of transit for work related trips into the RZ "sharply increased from 33% before the ALS to about 70% by 1983". In 1994 ALS was extended to a full day, resulting in an immediate 9.3% drop in traffic in and out the RZ. The ALS, despite its simplicity, succeeded in effectively restraining congestion in the RZ for more than 20 years. Before the implementation of ALS and the other complementary measures, the motor vehicle fleet was growing at an annual rate of 6%, and in 1975 the traffic volume entering the RZ was about 100,000 vehicles. After the government intervention, the fleet slowed down to a moderate 4% rate of growth, and traffic entering the RZ was limited to only 230,000 vehicles in 1994. Road Pricing Scheme (RPS) extended In 1995, congestion pricing was also implemented in urban segments of three major expressways, starting with the East Coast Parkway (ECP). The RPS, as it was called, also operated manually with paper licences to enter the expressways. In 1997, the RPS was implemented in the Central Expressway and the Pan Island Expressway. After the implementation of RPS, the Central Expressway Average speed at peak hour went to 67 km/h from the previous average of 31 km/h. This extension was necessary because some through traffic was diverted by the ALS to routes that bypassed the RZ, increasing demand on these arterials and creating a need for expanding the capacity of the