How well lane guidance works is a function of where you are and how well they've managed to get the maps fully populated with that specific data. I use the non-truck version of that unit and a Bridge unit (the 7" commercial device) and in the areas where I drive, the lane guidance covers just about all of the interstate entrance/exit areas. What they do NOT cover are any of the State highway entrance/exit areas. In a corresponding manner, you should be seeing that data on just about every notable interchange for an M road in the UK, but don't expect to see them on A roads and the like, even if they are 'limited access' and/or multi-lane.