An in-car navigation device has a route preview or simulation function. The name of the actual road along which the vehicle is simulated as moving is also displayed, just as it would be if the vehicle were actually travelling along the route. The status bar, or actually on the road itself. This ‘demonstrate route’ function is achievable because the device stores a database sequence of road names, together with the vectors and actions which define the roads of the calculated route (this route has been fully calculated in advance and stored in device memory). Records in this database that define the route can then be sequentially selected (say simulating progress at a rate that allows the entire journey to be completed in 15 seconds) and the device can then display simulated progress of the car along the vectors which define the roads of the calculated route on the map image.