General Motors will fit more than two million 2007 vehicles in the US and Canada with what is claims is the industry's the first factory-installed, fully-integrated off-board GPS navigation system - OnStar Turn-by-Turn Navigation.

The new service will be standard for the first year on a number of GM vehicles retailed in 2007 including nearly all Buicks and Cadillacs. The navigation system will also be available on many other GM vehicles through a $100 optional package upgrade during the initial year of service.

Customer demand for in-vehicle navigation systems is rapidly rising. According to a JD Power and Associates estimate, 1.2m 2005 model year vehicles in the US were equipped with factory-installed navigation systems, a 41% increase over the 2004 model year.

After the first year, customers can renew their package for $US299 per year, which also includes other OnStar services.

The OnStar navigation system allows a consumer to talk to a live advisor, who in turn sends directions to the customer's vehicle through their OnStar system. Directions are then automatically played through the vehicle's stereo as they are needed, triggered by the system's GPS capabilities.

A similar system is offered in the UK as an aftermarket/accessory item by Trafficmaster.