Experienced more of this issue tonight. Any Zed ran over causes the car to bounce off the ground, I expect hitting a zed to cause some bounce as if you ran over a person your car IRL would...

Though this seems to lose some sync with the terrain which at higher speeds can launch the vehicle.

Mowing down a herd of infected in a city will cause your vehicle to bounce a lot and potentially launch and crash.

Also, probably a 2nd issue. Infected AI is ONLY affected if the vehicles are in Drive. Reverse they just ghost through the vehicle. I'll make a new ticket for that.