The hardest thing with an exposed driveway is getting the right tree. Pyrus aristocrat is amazing as it is so tough (although perhaps not tough enough for brutal coastal winds) and it is beautiful. It retains a really nice shape, not getting too large and the addition of a white flower in Spring and then the great Autumn colour - it's a win in every sense. You do need to make sure you have enough space. This is perfect for a rural setting with a verge on each side of the driveway that is a minimum of 3m in width. You can go as close as 5m apart - I wouldn’t recommend that you go any further that 8m apart.
Either side of a large Driveway
3m required either side of a driveway
Pyrus Aristocrat - Ornamental Pear 5 to 8m apart
Foliage Colour: Green in Summer going red in Autumn