Concern continues to mount over the rising level of traffic on Britain's roads. It causes high pollution levels and is one of the main contributors to global warming. JONATHAN ISAACS looks at the progress of one of the solutions, clean fuel vehicles.

Traffic is the main cause of poor air quality in cities and large towns. It causes health problems, like asthma, and contributes around a quarter of all C0? emissions in the UK, the main cause of global warming. As many as 24,000 early deaths a year in the UK are laid at the door of poor air quality and it also causes a similar number of people to be hospitalised.

It has led Swansea and Neath Port Talbot councils to declare Air Quality Management Areas showing that pollutant levels are above Government recommended targets.

Hafod in Swansea and Margam and Taibach in Port Talbot are two areas where there is concern about poor air quality and the areas are closely monitored.

One way of dealing with the problem is to reduce the number of vehicles on our roads. But this is regarded as being less likely to work than developing vehicles that use cleaner fuels, like liquid petroleum gas, natural gas or electricity.

Even so, progress in this direction has been steady rather than galloping. Twelve years after the government set up the Energy Saving Trust, there are still only around 100,000 LPG vehicles in the UK.

The non profit-making trust's aim is to cut carbon dioxide emissions by promoting the sustainable and efficient use of energy. It is working to get more of us to use the new generation of fuels in our cars and has two initiatives with this in mind, PowerShift and CleanUp.

PowerShift is a programme that aims to kickstart the market for alternative, clean fuel vehicles in the UK. Grants are available and the aim is to make clean fuel vehicles become practical and economically viable. CleanUp aims to improve air quality and uses grants to encourage emission-reduction equipment to be fitted to commercial diesel vehicles.

According to the trust, the initiatives are becoming more successful. By the end of March this year it expects to have funded around 8,000 vehicles under the two programmes, compared to 5,000 in 2002-3, but the numbers are obviously still small. What will not help is the Department of Transport's decision not to provide additional funding which means new grant applications are now being put onto a waiting list.

Here in Wales the Assembly this week announced it was backing the CleanUp scheme with a grant of £250,000 for 2003-4.

It does not sound a huge amount although further funding of just over £1 million in 2004-5, and a similar figure for 2005-6, will be given depending on the scheme's success.

Assembly economic development and transport minister, Andrew Davies, emphasises the importance he attaches to initiatives like CleanUp which, in Wales, will be available to haulage firms and bus companies and some makes of black cabs. He says the result will be a cleaner, healthier environment for the people of Wales because harmful fumes will be reduced and air quality improved.

"This is a huge step towards improving health and environmental conditions for drivers, public transport users, cyclists and pedestrians,'' said Mr Davies.

"I have a strong commitment to sustainable development and this initiative will go a long way to helping reduce emissions from some of the most polluting vehicles on our roads and making Wales a cleaner and greener place.''

The job now is to convince more motorists that this is the way ahead and to take up the scheme. Bus companies in the UK have been slow to do so, with just one or two vehicles in a handful of fleets taking up the LPG or electric options.

But Energy Saving Trust chief executive Phillip Sellwood is optimistic that many more vehicles powered by the new cleaner fuels will be appearing in the UK over the next few years. Latest figures show that the number of vehicles powered by natural gas, for example, rose from just 217 in 2001 to 2,150 by the end of last year.

"This achievement is clear evidence that the cleaner fuel market in the UK is maturing and we have reached a stage where there is real choice available for consumers and fleet operators,'' said Mr Sellwood.

But many motorists still need to be convinced that LPG and other cleaner fuels are as efficient as petrol or diesel. There is also concern about the shortage of places to refuel the new generation of vehicles, although there are now more than 1,400 places available in the UK with dozens across South Wales.

Many motorists remain wary because when it comes to the new generation of fuels, slow-moving electric milk floats still spring to mind.

But technology continues to advance. Motoring experts are convinced that the day is not that far off when the fuels almost everyone uses today will be just a memory.