New proposals to reduce traffic congestion using Global Positioning System satellites may prove costly and ineffective in built-up areas.
A report published this week by the Commission for Integrated Transport, the government’s independent advisers, proposes all cars be fitted with a small unit linked to GPS satellites covering the national road network, including motorways andresidential areas. Drivers would be charged for using busy stretches of road during peak times.
The system would be introduced once increased investment from the government’s 10 Year Plan has begun to improve public transport, the report states.
But experts have questioned whether GPS is capable of providing comprehensive coverage, particularly within the UK’s congested cities, where tall buildings can disrupt signals.
Keith Wood, a consultant on communication systems for the Federation of the Electronics Industry, said GPS is currently only accurate to within 50-100m, severely limiting its effectiveness within cities.
‘GPS has its limitations, particularly in built-up areas. If you just want to clock a car as it goes on to a highway, and then again when it leaves, that would be possible. But if you want to pinpoint a car out of a number on a three-lane highway, that would be much more difficult.’
The system would be ‘more or less adequate’ on open highways, providing it did not need to be precise, he said.
Engineers in the US are working on a new version of GPS that may be more effective in urban areas, but it is likely to be some years before it is launched, and existing in-car receivers would then need upgrading.
As part of the CFIT’s proposals, charges would be collected via a smartcard on board the car, or billed in the same way as mobile phones. But fitting every vehicle with a receiver could make the proposals difficult or costly to implement, experts predict. A spokesman for Trafficmaster, which offers in-car traffic information through a network of infrared sensors on bridges and roadsides, dismissed the idea as ‘silly’. In-car receivers can be expensive, and every vehicle in the UK would have to be equipped with one to make the system fair, he said.
‘There would be a huge cost involved, and it would be a logistical nightmare.’
Making the receivers tamper-proof would also be a major challenge, said Edmund King, executive director of the RAC Foundation, the motoring organisation’s campaigning arm. ‘What happens if you disconnect the box? For any system to work, enforcement is important. Currently four per cent of cars do not have Vehicle Excise Duty discs.’
The receivers would have to be developed to offer additional benefits for motorists, such as satellite navigation systems, to make them more attractive to manufacturers, said King. ‘They would also have to be developed to international standards, so car makers would not have to install different devices in the UK and the rest of Europe.’