Driving distance (pgr_drivingDistance) is a query that calculates all nodes within the specified driving distance of a starting node. This is an optional function compiled with pgRouting; so if you compile pgRouting yourself, make sure that you enable it and include the CGAL library, an optional dependency for pgr_drivingDistance.
Driving distance is useful when user sheds are needed that give realistic driving distance estimates, for example, for all customers with five miles driving, biking, or walking distance. These estimates can be contrasted with buffering techniques, which assume no barrier to travelling and are useful for revealing the underlying structures of our transportation networks ...
