Science: Punctual buses] Are they off their trolley? - In London and Birmingham the long, uncertain wait at a stop may be ended by satellite and radio link-ups, says Tim Wickham

On Thursday, a conference entitled Making the Most of the Roads We Have will open in Coventry. The two-day event will look at how computers can help to alleviate congestion on our roads and improve public transport. But in London and Birmingham, information technology is already being harnessed in ambitious schemes. Between them, the cities have committed pounds 3.9m to developing computerised databases that gather information on bus movements and transmit it to displays at bus stops.

The information should help managers to pinpoint problems and so improve punctuality. As an added service to customers, it should give travellers greater confidence in the system and encourage them to use public transport.

London's pounds 1.5m pilot scheme, Countdown, began last November on the route from Sudbury in north-west London to King's Cross. A radio link connects buses to a central computer. Arrival times are sent down telephone lines to dot- matrix displays at 50 bus stops along the route. The displays are similar to those on the Underground, which tell passengers how long the next few trains will take to arrive. Tests on a second route, from Shepherd's Bush to Uxbridge, costing pounds 900,000, are due to follow in January.

The manager of London's Countdown, Stephen Balogh, believes that his system is likely to be more accurate in tracking bus positions and predicting arrivals on troublesome routes than Birmingham's pilot scheme, called Drive, which starts next summer on the most congested routes. 'It's relatively easy to be accurate with about 70 per cent of bus services,' says Mr Balogh. 'We have concentrated on the 30 per cent of problem situations to give us an overall accuracy level of something like a 90 per cent.' He believes that Countdown will pinpoint buses to within 10 metres, compared with Birmingham's 30 metres.

Martin Hancock, strategic business analyst at West Midlands Travel, the region's biggest deregulated bus company, talks of Countdown's preoccupation with 'spurious accuracy'. 'Ten metres hardly makes any difference when you can see a bus coming from a few hundred metres away,' he says.

Unlike Countdown, which uses beacons at the side of the road to plot the position of buses, Drive has tapped into satellite technology to monitor the 50 buses in the scheme. Each vehicle will be fitted with receiving equipment that transmits information to a central database developed by the computer company ICL.

The arrival times of the next three buses will be flashed on electronic screens at bus stops. Computers on street corners and in travel shops will give information about timetables and fares. Richard Betts, from ICL Enterprises, says of the Midlands scheme: 'Our overriding aim is to get more people on public transport by giving them better information. They can make informed decisions about their choice of transport - and not be left waiting in the rain, unsure when the next bus will turn up.'

For Mr Hancock, the point of Drive is not whether technology can be made to predict buses' movements down to the split second, but how it will relieve congestion by providing better information. If people can tell exactly when a bus is due, they are more likely to use the service instead of going by car. 'The real issue is to give customers confidence in that information. I think the London scheme is missing the point,' he says.

Improved quality of life is one of the goals for Centro, the West Midlands traffic authority, which runs Drive. 'More people on buses means less pollution and congestion,' says Mike Parker, head of operations at Centro. 'We get an average of 39 people per bus travelling into Birmingham in the rush hour, compared with a car occupancy rate of just 1-2 people per car.'

One of the targets of the scheme is the car-bound businessman. More ought to travel on public transport, believes Livvy McGrath, a spokeswoman for Castle Rock Consultants, which specialises in information technology in travel. It is designing a hand-held microcomputer, based on a personal organiser and a mobile phone, that travellers in the West Midlands could use to tap into a central database of travel information. Tests of the microcomputers will start in Birmingham next year.

A pounds 50 keyboard device is also being developed, by Cambridge-based General Information Systems, designed to be used at home. Travellers could tap into the travel database before venturing out of the house.

If successful, Drive, which is partly funded by the European Union, could be extended to all routes operated by the West Midlands' 40 deregulated bus companies, says Mike Parker.

In London, Stephen Balogh has a 10-year target: 'By then we hope to have 4,000 stops - a quarter of the capital's total - equipped with electronic displays.'

David Jeffrey, director of the transport consultants Wootton Jeffreys, one of the organisers of this week's conference, believes that the Government could do more with technology. 'With the increasing unavailability of money and an increasing pressure on the environment, they should be looking at the opportunities offered by advanced traffic systems to use what we have more efficiently as an alternative to building new roads,' he says.

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