Annual satnav sales exceed two million units and nine million vehicles are already fitted with navigation systems on Europe's roads.

The survey will take place this year in seven European countries - the UK, Belgium, France, Germany, Italy, Netherlands and Spain – and will then be repeated in 2009 and 2010 to identify changes and developments. EurotaxGlass's and Navteq believe the positive impact of navigation systems on residual values and total cost of ownership is often underestimated and can negatively influence satellite navigation purchasing decisions. Kevin Gaskell, president of the EurotaxGlass's Group, said: "The conclusions of this study should result in a significant reappraisal of the impact of regular system updates on residual values. “This is a key point not only for fleets but also increasingly for individual drivers.”