Sometimes, people can't react in time to oncoming traffic, or they just don't notice. By the time they know how to react, it might be too late. So why not let the honk of an oncoming vehicle do more than warn? Why not enable it to actually push people away?
The sonic boom horn is a device which blasts a wave of sound that both warns people as well as pushes them away. This is because the sonic energy blast is creates a pocket of air pressure that is strong enough to displace bodies that might be in its path.