Rocksteady decided to not include the Batmobile, because it would be unable to travel on the city's broken terrain. Instead the team focused heavily on gliding as a sufficient means of transportation, and it was considered that putting Batman in any vehicle would make it a completely different game.

By the time they had programmed Batman to dive and glide between buildings of the asylum, the adaption of the gameplay to the city was considered natural.
Contributed by DrakeVagabond