DRIVING his car from A to B may seem ''efficient'' to Peter Spinney (May 19) for his private journeys, but using his own definition applied to a more global audit gives another view for the discussion.

I recall an American study from the 1960s which divided the distance of journeys made by automobile by a combination of time to drive the miles plus all the other time needed to make the car travel possible: like hours spent working to pay for buying, taxing, fuelling, servicing, parking, and generally tending to the car's needs. The time and costs from accidents, fines, police, and courts were excluded but the final speed still worked out at only about five or six miles per hour!

Twenty million car owners in Britain do not show that car travel is efficient. They are the reason for the urgent discussion. Their existence is probably due more to Aladdin and his magic carpet or Star Trek and the teleport machine. It's the idea that the motor car can easily transport us somewhere else with virtually no effort which has seduced man for a whole century.

Like most extravagant promises the reality proves a lot more problematic and the costs hardly bear thinking about. The absolutely massive investments made in the car have, no doubt, produced a technological marvel but the sacrifices that have been demanded have also been massive.

Even if we ignore the pillaging of the earth's non-renewable resources to build and run the motor car and the lives lost and maimed along the way, the freedom and mobility yearned for have not been delivered. Even after subjecting our environment and way of life to the needs of the car we still end up with congestion and pollution.

All the effort and passion devoted to the car have produced what may be seen as a beautiful, sexy, prestigious, family-friendly, or even frugal extension to ourselves and our lives. The motor car has also become ridiculously cheap to buy and run compared to any other sensible measure.

We can easily turn a blind eye to the real costs. They get written off, subsidised, ignored, or in the case of natural resources are simply not repayable. This distorts the way we see the machine and everything connected with it.

We look for fun or excitement from driving but end up with frustration, boredom, and road-rage. Instead of well-being we get poor health, and sometimes tragedy, individually, for communities, and mother earth. Once again submission to the lure of an artificial solution has dehumanised, delivered less, and cost more than hoped.

The cry that we need the car for modern living begs the question, which came first? The disruption of our towns, villages, and swathes of countryside along with the dispersion of housing, industries, and services which seems to have resulted from a need to justify the existence of the car so many desire.

The more difficult job now is to get the genie back in the bottle. Walking and cycling are dismissed by Peter Spinney as not viable for most commuters. That will depend largely on whether life is arranged around a human scale of mobility. The bicycle is an extremely efficient machine, in terms of distance covered for energy expended. The good health and enjoyment, which Peter Spinney mentions, are added bonuses. Above all, walking and cycling are civilised, human modes of travel which are powered and controlled by the individual who stays in touch with the real world.

David Begg is also criticised but he at least is tackling the unequal task with a range of laudable and creative solutions in an attempt to allow everyone to keep mobile, including the uneconomic and inefficient private car.

Peter Hayman,

60 Bank Street, Kilmarnock. May 21.

I HAVE no desire to engage in techrimonious debate with Peter Spinney (Letters, May 22) but I do wish he would compare like with like.

It is well-known as Peter Spinney suggests that the thermal efficiency of power stations may be as high as 40% but it is equally well-known that there are further dissipative stages before the final load. In the case I mentioned there are generation losses, transmission line losses, battery charge/discharge losses, as well as the car running-gear losses. At the road wheels of the battery electric car, my figure of 20% is not unrealistic.

Peter Spinney did send me a copy of the article on which he bases his allegations but I do not share his conclusions that cars made in 1987 were six or eight times more polluting than those made today.

As I read it the article makes out that the worst offenders are these old cars, but the obvious reason is that the engines are worn, not that they were bad polluters when new a decade ago. Indeed the article cites its worst case, a 1987 Sierra with no catalytic converter and 100,000 miles on the clock.

Chris Parton,

40 Bellshill Road, Uddingston.

May 23.