While most satnavs ironically take us wildly off course burning more fuel and igniting more anger, the Econav promises to find drivers the most fuel-efficient routes. Its makers, Vexia, claim that the gizmo cuts carbon emissions by 30%
It also indicates what gear you're in, what your optimum energy efficient speed would be, as well all the usual map features. In addition you can select your vehicle from a list of 6,000 to find the closest match in terms of fuel efficiency based on acceleration and engine size etc.