Airbags will deploy in collisions that occur at any angle as they protect the occupants of the car from many different angles. A rear collision could also result in the occupants slamming their heads forward on the dash or steering wheel so the airbag would need to be deployed for safety reasons. Also, many cars now have airbags located all around the perimeter of the car. These airbags deploy based on where the car is hit. For example, I was in an accident where we were hit on the front driver's side wheel. Both front airbags and all of the driver's side airbags deployed in the rear and hatch. However, the passenger side airbags did not deploy since that side of the car was not hit.
