TfL opts for alternatives to satellite tracking

Satellite tracking technology is still not sufficiently advanced to enable pay-as-you-drive road charging, according to the results of Transport for London (TfL) trials.

TfL staged comprehensive tests of satellite tracking across London (Computing, 5 October), but has ruled out implementation in the immediate future because back-office functions such as billing were still prone to errors.

The organisation is planning tests of charging based on distance travelled next year after the trial demonstrated some significant improvements. A combination of tag and beacon technology and number plate recognition was found to be more suitable for congestion zone charging.

TfL global positioning system architect Nick Williams says the trial tested all aspects of the technology, including back-office applications, not just performance of the on-board tracking unit.

Improvements in technology led to the average location error dropping from 9.7 metres to 6.7 metres, but the best-performing system still had an average billing error of 0.86 per cent. ‘That is nowhere near what is required in terms of billing accuracy, but the gap is closing,’ said Williams.

The Department for Transport is pressing ahead with road-user charging plans that could form the basis of a national scheme, and is working with local authorities to develop regional pilots.

Gartner analyst Mike Williams says satellite tracking technology is evolving and TfL is wise to revisit trials next year.

‘While TfL is likely to have encountered significant errors, the launch of the Galileo satellites is likely to enhance vehicle positioning accuracy,’ he said.

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Further reading

London tests satellite tracking

London looks at car tracking options

London reviews road charge IT