With a random killing you might get indeed away, but murders are usually targeted. In case a deadly accident happens, and it can be proven the driver had a conflict with that person, it does turn the case around.

Murder is with the intention to kill. This would apply for using a car as a weapon as well and courts do go after these cases in practice, of sniping a target with a car.

But they are too lenient on deathly accidents with gross negligence.