Thanks to researchers at Cranfield University, you don't have to feel bad when you plow into a group of pedestrians who are crossing the street too slowly. They have designed an external airbag that mounts to your hood at the base of the windshield. Research shows that this is the area where a pedestrian's head is most likely to hit in an accident. "Test results indicate that the system works extremely well. When fitted to a demonstrator vehicle not originally designed with pedestrian protection in mind, the results were well inside all current legal criteria for pedestrian protection currently in force in Europe," Roger Hardy of the university's Cranfield Impact Centre said.