Motoring: Small and perfectly formed

Would you buy a car that flaunts high technology and urban environmental friendliness? Or would you feel you had to wear a paper bag over your head? The car concerned is an Opel MAXX, developed by General Motors' German arm. It is built around a skeleton of extruded aluminium sections, weighs three quarters as much as a Vauxhall Corsa, has a 1.0-litre three- cylinder engine able to do 70mpg, and is shorter than a Mini.

And it does look exceptionally cute. You almost expect to see a giant aerial on its roof, and a giant person operating a giant radio-control transmitter nearby. But the MAXX is no toy. Despite its small size, it is designed to cope with big crashes. A lot of its aluminium structure is left visible, to give a visual impression of strength. The plastic panels that fill the gaps in between are removable, so you can make the MAXX into a draughty beach buggy should you so desire.

The MAXX's compressed styling is the work of Michigan-born Danny Larsen, a graduate of Pasadena's Art Center College of Design, who now works with Opel's advanced projects. But he's not your regular car designer: "I'm not really a car nut, not like a conventional designer. I like designing functional things. I'd be just as happy doing ski boots. It's embarrassing; people ask me what I think of a certain car, and I don't know it."

The first MAXX prototype, fitted with a low-power electric motor to enable it to move unaided, was unveiled at last year's Geneva Motor Show. Project chief Hans Demant was handing out questionnaires to show goers to find out what they thought of the MAXX and, crucially, whether they would consider buying one.

The response encouraged Opel to develop the project further, building in the company's new three-cylinder engine which is officially destined for a new entry-level Corsa. It would also act as a test-bed for other future developments, including aluminium suspension components and magnesium wheels to save weight, and a new method of gearbox control to make for easier city driving. MAXX 2 is the result; Opel even got it registered in Mannheim so it could wear an MAXX 2 number plate.

I took this fully functioning second version for a test drive. Open the door, pull a lever in the seat back, and the whole bench-type front seat swivels towards you. This for easy access to the back where there's a small, removable bench seat in what would otherwise be the load bay. A little boot area remains behind this bench. If you want to leave the rear bench at home, you can fold it up like a picnic table and carry it away by its built-in handle.

With the front seat locked back into place, you sit high with a fine view over the snub nose - just what you need in the urban streetscape that would be the MAXX's intended habitat. Stretching across the cabin in front of you is a stout C-section aluminium extrusion, with the instrument pack, a telephone and the passenger's airbag nestling within the C and storage trays on top of it. There's neither a gear lever nor a clutch pedal, but next to the computer-screen instrument face is a large rotary knob which selects parking brake, automatic, manual or reverse.

It's easy to make the MAXX go. Start the engine, switch to automatic, press the accelerator and you're off. Electronic servomotors switch between each of the five forward gears in what is, mechanically, a conventional manual gearbox. If you want closer control, you can switch to manual and flick sequentially up or down through the gears with a paddle switch positioned a finger's reach from the steering wheel. This part of the system, which is similar to a Grand Prix car's gearchange, works brilliantly because the gearshift happens exactly when you want it to.

And the engine? It has the deep, slightly gruff note typical of a three cylinder, but it spins smoothly and pulls strongly for one so small (it's actually 973cc). And it has a host of clever features, such as hollow camshafts to save weight, miniaturised valve gear, ignition and fuel injection, a reusable oil filter canister easily reached on top of the engine, and four valves per cylinder. It needs virtually no maintenance apart from oil and filter changes, and with three cylinders instead of the usual four it generates less friction and is more energy-efficient. All told, it's as green as a petrol engine can be.

And it's a delight to drive a show-car-turned-prototype that works so well. Enough for Opel to take a deep breath and build it, transforming the company's image from being a maker of staid stodge to one of cutting- edge credibility? I'm afraid not. As ever, the reason is bound up with risks and money. Opel is not convinced that all those who have said they would buy would actually pay up when it came to the crunch. It's the paper bag factor at work.

Opel's engineering director, Peter Hanenberger, brings us back down to earth: "To begin with, we have problems with crashworthiness with such a short car. Our research into vehicles shorter than a Corsa has found that women with children reject them because they think they are not safe for the kids in the back. Then there's price. We have to make a profit, and the MAXX would be expensive to make. For what we'd have to charge, our customers could buy a bigger Corsa."

That's true, but wouldn't people be willing to pay for something so unusual and original? And wouldn't having the MAXX in the range in turn make cars like the Astra and Vectra seem more interesting? "You're talking about a halo effect," says Mr Hanenberger. "But we still have to generate a profit afterwards. And the figures from our marketing people suggest we shouldn't build the MAXX.

"How much modernity can a customer take? What if there's an economic downturn in five or 10 years, and people go back to having just one car? We have to plan for this. But we're very encouraged by the response to the MAXX. We'll continue studies, we'll use some of the weight-saving ideas in future production cars, and we might have a longer, full four- seater development of the MAXX at the next Geneva Show."

Meanwhile Rover is planning to launch an all-new Mini by the end of the century. If Opel misses its chance to compete, it could be kicking itself for a long time.