In-car satellite navigation (sat nav for short) devices are designed to get you from A to B as quickly as possible without reading a paper map. Sat navs can check where you are, tell you where you need to go, plan the best route to get you there and help avoid traffic jams and other road hold-ups. They come in different shapes, sizes and types, you can choose from simple models to more advanced sat navs and opt for fitting the sat nav in your car or have a device that can easily be attached and removed.

Why should you buy a sat nav?

Letting your sat nav tell you where you need to go and how to get there takes away a major worry, especially if you're driving around an unfamiliar town. This helps to keep you calm whilst driving, and if you're calmer you're less likely to get stressed and make mistakes.

Not only that, but a sat nav can actually save you money on petrol. When it works out your route, ask it for the most economical option and it'll adjust the route to make it more fuel-efficient. Along with fuel economy, the other main priority for most people is to save time, and that's where the sat nav really shines. If it looks like there's going to be a delay on the original route due to developing traffic jams or road works, the sat nav can automatically redirect you as you drive.

Using a sat nav

Once you tap in your desired destination, your sat nav works out the best route. In most cases you get the choice of the shortest time, shortest distance or most economical route. You may want to avoid motorways, or make sure you pass through a specific town on the way to your final destination; many sat navs offer this sort of flexibility, and more.

Once you've chosen your route, the sat nav calculates an estimated time of arrival that updates automatically as you drive along. The directions are displayed on the screen, showing when you need to turn, or even indicating which lane you need to be in. These visual directions are also supported by voice instructions. Choose from a range of voices built into the sat nav or, on some models, you can download additional options.

What to look out for:

Mapping

Sat navs are usually supplied with extensive maps of the United States. If you need to travel further afield, models equipped with maps of Europe are available as well. You can download updates from the internet to keep your maps up to date.

Screen size

Touch screens for sat navs range from 3.5 to 5. A larger screen can make it easier to enter your instructions and see the directions displayed; just make sure you place the unit where it won't obscure your view of the road ahead.

Other features

Many of the features available you will expect to be included with a sat nav, but there is one or two that may surprise you.

Traffic updates

Many sat navs receive instant traffic jam information, and keep you updated on the road situations as they develop.

Dynamic traffic routing

One step up from simple traffic updates, this feature not only knows where the delays are, it intelligently re-routes you to minimize any hold- ups.
Advanced routing

Sat navs fitted with advanced routing use knowledge of traffic flow trends to precisely plan your route according to the amount of traffic and the time of day.

Speed camera alerts

This warns you about speed cameras before you can see them and reminds you of the speed limit so you can drive safely, and legally.

Points of interest

This feature directs you to essential services such as petrol stations or where the nearest cash point is, but also to places like restaurants, cinemas and tourist attractions.
Parking location guidance

Take the sat nav out of the car with you when you park and it'll make a note of where you've parked in order to guide you back there later. This is potentially a huge time saver if you're leaving your car in a large car park or an unfamiliar part of town.

Bluetooth

Connect your mobile phone wirelessly to your sat nav to enable hands-free calling.

Advanced lane guidance

As you approach key junctions and roundabouts, the sat nav displays a detailed 3D view to clearly show the correct lane and exit.

Voice-activated navigation

Just tell your sat nav where you'd like to go instead of typing it in.

FM transmitter

An FM transmitter converts sat nav instructions (or music from your MP3 player) so you can hear them through your car speakers, via your car stereo.

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