I WAS sitting in traffic the other day with the engine ticking over when I noticed the fuel consumption meter going down regularly.

This brought home to me the fact that if you drive in traffic a good deal, you need a car with stop/start, which really helps keep economy up.

However, the engines in some cars fitted with this fuel saver will stay off only if the footbrake is depressed, which means that at night, the brake lights of the car are often dazzling the driver behind.

But as long as either handbrake or footbrake are on in the imposing and beautifully built new Audi A4, the engine does not restart - a much better system.

The A4 has already won loads of accolades and it really does drive well, smoothly and very quietly at all speeds.

I drove the 2.0-litre TDI auto with the Audi version of the VW Group's marvellous seven-speed DSG gearbox - still one of the best automatics in the world.

It's called S tronic and really is all things to all men, seeming to know how the driver wants it to react at any given moment.

There are paddles behind the leather covered wheel to do the changes manually, but in Drive or Sport modes, it does everything so well that I cannot imagine any owner would be bothered.

There's plenty of smooth performance from almost any speed helped by a quick kickdown and the car is a joy to hustle across country when there's not much traffic about.

Driven carefully it should top 50mpg, but that's nowhere near the government figure of 72mpg, and this car was showing only 38mpg on the trip computer when it arrived.

The road holding and handling are sublime, with tremendous grip and marvellous balance on dry roads.

Above 45 miles an hour, the ride is excellent too, but I found it quite lumpy on rough surfaces in town, and I'm pretty sure this was caused by the very low profile tyres and big alloy wheels.

It's the only dynamic drawback for this otherwise excellent car but private buyers would be much better off buying the petrol, since on average mileages the diesel will yake you 10 years to break even.

SE Ultra spec brings stability and traction control, alarm, climate, cruise, front and rear parking sensors, cloth seats, bluetooth and a CD autochanger with aux and USB.