Business Analysis: Beware of siren voices leading you astray ...

"So you don't need a road map anymore?" my friend asked as I proudly demonstrated the satellite navigation system fitted to the new, sleek Honda Accord Tourer I was testing for this newspaper. "No," I replied confidently. "Old hat. No one needs those anymore."

"So you don't need a road map anymore?" my friend asked as I proudly demonstrated the satellite navigation system fitted to the new, sleek Honda Accord Tourer I was testing for this newspaper. "No," I replied confidently. "Old hat. No one needs those anymore."

Nearly right. If, as was the flaw in my plan, you can't remember the name of the street you are going to, no hi-tech device in the world is going to help you out, and few satnav maps are as detailed and as user-friendly as an old-fashioned paper A to Z for looking around an area for a name or place you vaguely know. We all got to the pub eventually but it was a little less effortless than I thought. But when you do have a firm address or just a postcode, your satnav system will, you may be assured, always get you there eventually.

However, there are snags. The software needs to be up to date. A colleague testing Volkswagen's flagship £50,000 Phaeton limousine was surprised to learn, for example, that the house he lived in, built five years ago on the outskirts of Ely in Cambridgeshire, was not supposed to exist.

Some satnav systems will give you information about traffic jams; some will not. The ones that do not may not be particularly helpful about how you can avoid the jam, as they lack the sort of nous most decent cabbies possess around town.

You may find it tricky to ask the system to avoid a clogged up area if you are already on the move because you have to spend too much time pressing buttons on the dashboard. Which is the major drawback of the satnav revolution; those pretty little screens and siren voices do tend to distract your attention from the road and avoiding hazards. While trying to obey that charming, invariably soft female voice telling you to, "Bear left. Bear left. Second left turn ahead. Left turn. Turn left. Bong. U-turn. U-turn", you could well have ploughed into a bus.

The author is the editor of The Independent's Motoring section