TomTom has teamed up with Vodafone to offer HD Traffic - a live traffic update service that will soon be available in new portable navigation devices (PNDs), and as an upgrade to older models.

HD Traffic works by synchronising raw GSM data of mobile phone movements from Vodafone with traffic info from local authorities. The information is picked up by a GPRS modem built into new TomTom PNDs, and as an add-on for existing TomTom satnav owners.

TomTom says HD Traffic gives you 20 updates an hour (one every three minutes), which is five times more than its nearest rival can offer. HD Traffic can even calculate the traffic and travel times on alternative routes just in case you hit a snag on your journey.

ONE XL HD Traffic

Of course using HD Traffic isn't free - you'll have to pay a monthly subscription of €9.95 (£6.98) in addition to any cash you stump up for the PND, add-ons or additional TomTom Plus services like Safety Camera updates. Part of this fee goes to cover the cost of dialling up for updates via the built-in modem.

The first device to use the new HD Traffic service will be the cleverly named ONE XL HD Traffic, which is already on sale in the Netherlands for €399 (£280).

However you'll have to wait until mid-2008 before you can get your hands on a UK specific version. Country specific versions for other territories have yet to be rolled-out too.

Key features of the ONE XL HD Traffic include a touch-sensitive 4.3-inch screen, 1GB of internal memory and an SD slot so you can add additional maps to the Western European ones already built into the device. The ONE XL HD Traffic also includes a two hour Lithium-Ion rechargeable battery.