Increasingly being fitted as standard to new cars and cheap to buy as an after-sales 'accessory', the in-car SatNav¹ system is gradually and stealthily insinuating itself into an ever increasing number of people's lives.

The aim of this entry is to point out some of the advantages and pitfalls of the system and to gently steer users away from the more dangerous/embarrasing problems that may occur when using it.

So how does it work then?

To give a simplified version, the system combines a GPS receiver, one or more digital street maps, linked to databases including details such as street numbers, speed limits, post codes, fixed speed traps, etc.

Using the basic system couldn't be easier, simply tell it where you want to go and let it calculate the best route for you to take, it'll then show your present location on a 3D-perspective map, with arrows pointing where you should be going, in addition to telling you how far away your next junction is, which way you should turn when you get there, how far it is to your destination and how long it should take you to get there.

Sounds simple, so what can possibly go wrong?

Oh, the list is endless... This seemingly innocuous machine has an arsenal of tricks up its virtual sleeve, all aimed at leaving the innocent motorist with either egg on their face, an expensive insurance claim or the embarrassment of being towed out of a duck pond by a local farmer in his tractor.

Here are a few of the more common mistakes people make when using a SatNav:

Great, now I don't need to put up with my significant other's non-existant map-reading skills!

Wrong! On so many counts...

Firstly, as a driver, you can guarantee that the moment in a journey you need the advice of a satnav system the most will be the instant you will be simultaneously attempting to change gear, look over your shoulder and check for traffic coming from all directions at an unfamiliar junction, whilst at the very moment the dulcet tones of the recorded voice on your satnav tells you "At the roundabout, take the XXX th exit", your dog will decide to bark, your kids in the back will start shouting and the passenger in the front seat will either turn the radio up full blast or ask you what you want for dinner later on.

All this is a silly way of illustrating the fact that, as a driver, the moment you need directions the most is usually the moment you have the greatest number of things to concentrate on and absolutely no hope of taking the time to look at the map or listen to the voice.

So what can I do about it?

Sorry, but you haven't made your significant other redundant just yet...Instead of replacing them with the satnav, think of it as a replacement for the map itself. At least with a satnav they can't mix up left and right because the map's upside down or loose their page at a vital moment.

Let your passenger continue to navigate, they've got more time to see what's coming up on the road and check the satnav screen against what is actually happening ahead. For instance, as a driver it's far easier to follow instructions like "Follow that red car", than it is to listen to "Take the third road on the left", and then try and figure out whether or not the driveway you just passed was actually the first exit or not.

Another common problem is that if you, as a driver, are relying solely on the voice of the satnav system to direct you, for instance, a common fault made by most systems is when driving along a minor road which is approaching a main road at an acute angle², frequently the SatNav will tell you "At the junction, turn left", meaning that you should turn left onto the main road, however, from your perspective, you are simply carrying on straight ahead, albeit after having to slow for a 'Give Way' sign. And if there is a driveway or entrance to a farmers field to the left of the junction, you may end up either parked in someone's garage or needing that farmer's tractor.

This, again, is where your passenger comes in. In a perfect world they can warn you of the problem in advance, or, at the very least, they can scream hysterically "STOP!" before you reach the duckpond or ram some poor unfortunate soul's lawnmower/newly-cleaned Volvo estate.