Are assaults on vehicles possible?

Yes, you can already land on a vehicle as an assault, meltabombs and krak grenades stick to vehicles, and power weapons are intended for use against vehicles.

Either you smash them with an attack from the air or you brace yourself to hit them as they come at you – for example, you can start charging your power fist or thunder hammer so you smash a vehicle as it’s going to run you over.