Singapore will explore the use of satellite tracking technology to update its Electronic Road Pricing system and reduce road congestion, a government minister announced this week.
"With emerging technologies available, our Land Transport Authority has been studying potential technology applications for our second-generation [road pricing] system. One of the key technologies identified is a Global Navigation Satellite System (GNSS) which makes use of satellites to determine the position of a vehicle," said Raymond Lim, the Southeast Asian city-state's minister of transport, according to a transcript of a speech given on Wednesday.
GNSS is a generic term that encompasses systems like the Global Positioning System (GPS), which rely on a network of satellites to pinpoint a user's location with varying degrees of accuracy. Such systems can have trouble working in cities, where radio signals sent by the satellites can be disrupted by tall buildings. However, these problems can be mitigated with the use of Assisted GPS (A-GPS) technology and triangulation done using cell-phone towers. To apply such technology to road-pricing, an in-vehicle unit would have to first determine its position from the satellite signals, then report that information back to the road-pricing system to enable it to calculate the charges to apply.
Singapore's road-pricing system is designed to control road congestion in downtown shopping and business districts and on major roads. The current system, rolled out in 1998, depends on a network of gantries erected at strategic locations around the city. In addition, every vehicle sold in Singapore is fitted with a device, called the In-vehicle Unit (IU), that contains a short-range radio transmitter and a smart card reader.
Cars and other vehicles are charged a fee as they pass under a road-pricing gantry. Rates for cars range from $0 to S$3 (US$2.15), depending on the location, day of the week, and time of day. The road-pricing charge is automatically deducted from a smart card inserted into the IU. If a driver forgets to insert a smart card into the IU or the smart card does not have enough stored value to cover the charge, a bill for the charge, plus a S$10 processing charge, is sent to the owner of the car.
By putting a price on the use of certain roads at different times of the day, the road-pricing system uses market principles to manage road congestion. However, the system isn't perfect.
As the number of cars on Singapore's roads increases, more road-pricing gantries have been erected to manage growing congestion. According to statistics published by Singapore's Land Transport Authority (LTA), there were 66 road-pricing gantries on Singapore's roads in 2008, up from 45 gantries in 2004 -- an increase of 47 percent over four years.
But these new gantries haven't solved the problem as erecting new road-pricing gantries in one location can lead to congestion elsewhere as drivers look for cheaper alternative routes to their destination.
In a bid to find a more effective way to manage Singapore's growing congestion, LTA will issue tenders for technical proposals for a satellite-based road-pricing system, Lim said, adding that trials would be carried out to determine whether the technology is accurate enough for daily use. And that means it may be some time before a satellite-based road-pricing system is rolled out in Singapore.
"We expect the development and testing of new [road-pricing] technologies that are suitable for Singapore's conditions to take some years, before it is ready to be launched and implemented," Lim said.