The animal landed on the bonnet of a red Hyundai i10 saloon, smashing the windscreen and causing extensive damage to the front of the vehicle.
The driver, Robert Orton, 82, said he had been visiting friends at Cobo and was returning to his home in the Forest, via the Vazon Coast Road diversion.
'The first thing I saw was five horses galloping along the road towards us going in the direction of King's Mills,' he said.
'We slowed down to let them go by when the horse jumped suddenly from my left and landed on the car. It was like an explosion, absolutely frightening.
'I just feel so sorry for the horse.'