In the last six months, TomTom has released arguably the most significant development in sat-nav for years - HD Traffic. But, knowing it's onto a good thing, TomTom also charges you an arm and a leg for devices such as the TomTom GO 540 LIVE, plus a monthly subscription.
A lot of people don't use their cars enough to justify the expense, making the budget end of the market much more sensible. Fortunately, TomTom is also moving some of its premium features down to its more keenly priced models, the One and XL. Both have been redesigned as well. We took a look at the new version of the XL with full European maps.
The most significant premium feature to be making its debut at the lower end is TomTom's IQ Routes system, which we first saw in the GO 930 Traffic. Traditionally, sat-navs have calculated their routes based on fairly dumb, static data - usually either the shortest distance or the speed limit on the roads in question. So, with the latter setting, motorways will be favoured over local roads.
But there are major issues with either method. As anyone who lives in a city will attest, heavy traffic often means you don't travel at anywhere near the speed limit on many urban roads. And, if your shortest route takes you down country lanes where it's only safe to do 10mph, your journey could end up taking hours longer than expected.
TomTom's IQ Routes takes a more savvy approach. Instead of using the speed limit for calculation, it uses historical data for the average speeds vehicles have actually travelled at on given roads. Even better, the latest version even takes into account the day of the week and time of day. So a weekend route will be entirely different to one calculated for weekday rush hour.
For example, rather than sending us down the A406 from the A40 to reach the M4 heading out of London, during rush hour IQ Routes instead directed us to the A312, which is historically less frequently jammed at this time of day. This is the route most Heathrow taxi drivers will take, too. In general, we found IQ Routes calculated much more sensible options most of the time, although of course it couldn't cope with incidental traffic holdups. It also lacks data for roads which are used very infrequently, such as rural farm lanes.