No, I get that it has limitations. But in this case, if KW doesn't put himself out there in the 'line of fire', there's no way he gets killed by a race car on the track that night. In the other scenario, if the driver is driving the limit, then he likely still gets hit and ends up in a wheelchair.
But if Ward were not driving at all he would not have been killed. It's a mix of legal causation and contributory negligence. The problem Stewart will have is res ipsa loquitur - nobody else hit Ward and he did. After he may have gone slightly off line. It would not be that difficult to put forward a case that Ward would have known where it was safe to stand and could not have foreseen Stewart's slight wiggle.
As an example, an off duty policeman riding his own personal motorcycle was hit by a car. The driver of the car was cited for being at fault and was found guilty in that case. The policeman was permanently disabled and forced to retire at the age of 27. He filed suit against the lady that hit him and was awarded only his medical costs, with no damages at all for either his pain and suffering or his lost capacity to work going forward. According to a member of the jury, they agreed with the theory put forward by the defense attorney that the policeman should have know that there is an inherent risk in riding and by doing so accepted that risk.
That is beyond appalling and as a decision would take about two seconds for a competent judge to sling it out. And bar everyone on the jury from ever making any decisions on anything ever again.
But I would like some sort of reference for that. Because the jury have made a decision there based on law (acceptance of risk is a legal point). They are not qualified to do that. Indeed, given their decision on that, they are not qualified to breathe.
If some inattentive driver were to rear-end me and put me in a hospital bed for the next 6 months, I wouldn't have any grounds to recover from him in civil court for damages because technically I'd be breaking the law by having no headlight, even though that had nothing to do with the accident. Scary thought.
That ought to be a different case, as if you were rear-ended, not having a front light would not have had any effect on the accident. So there would be no contrib. Like running out in the road right into a drunk driver. If a sober driver would have hit you anyway, the fact that the driver was drunk would not get you damages. (He might be prosecuted for drink-driving, but not for the accident.)
But as I said before. American law. I have never had a positive experience dealing with it.