Yes but the impression that I get from the way you are saying it is that's its hard for the plaintiff to prove and I don't think it is.
You think it's easy for the plaintiff to prove to the jury that an 8,000 pound van is no different than a 33,000 truck?
You're right, I think it's incredibly hard to prove to a jury that there's no difference, considering every member of a jury has seen the difference for themselves every time they go for a drive.
As far as the vehicular homicide statutes you quote, they are all based on intent or some other criminal act such as a DUI. We are not talking intent here, hence the civil suits.
They aren't all based on intent or other criminal acts, actually. Most are, yeah. Some statues specifically require either intent or a homicide while in the commission of a crime, such as DIU, reckless driving, etc. Some states simply include the negligent operation of a vehicle as cause for the charge. But the states where it isn't specifically mentioned as a prerequisite for vehicular homicide, people are charged with negligent homicide, instead. Others have varying degrees of vehicular homicide, with the most severe degrees being the ones that involve intent or the commission of some crime. None of these are civil crimes. If someone dies because of your improper actions while driving a vehicle, be it driving while intoxicated, speeding, reckless driving, of driving impaired (including fatigued), you're gonna get charged, and likely convicted, of some degree or another of vehicular homicide, or at the very least negligent homicide.
If you drive while impaired (fatigue, high fever from the flu, whatever) and have an accident where someone is injured or killed, even if you did nothing else wrong, it could be as simple as your reaction time being slowed down and you broke no traffic or other laws, you're willfully and intentionally operating a vehicle in a reckless manner, a danger to others on the road. That's viewed as intent in every courtroom in the country, no different than if you willfully got drunk and got behind the wheel. If that accident happens after 20 straight hours of driving, you're screwed.
Incidentally, criminal and civil lawsuits aren't mutually exclusive. One doesn't except someone or preclude the other. People often end up in court for both.