Those are not the only elements that must be proven in CA.
Just for the misdemeanor per PC 192(c)(2) the state must show:
To prove that the defendant is guilty of vehicular manslaughter
with ordinary negligence, the People must prove that:
1. While (driving a vehicle/operating a vessel), the defendant
committed (a misdemeanor[,]/ [or] an infraction/ [or] a
lawful act in an unlawful manner);
2. The (misdemeanor[,]/ [or] infraction/ [or] otherwise lawful
act) was dangerous to human life under the circumstances
of its commission;
3. The defendant committed the (misdemeanor[,]/ [or]
infraction/ [or] otherwise lawful act) with ordinary
negligence.
AND
4. The (misdemeanor[,]/ [or] infraction/ [or] otherwise lawful
act) caused the death of another person.
For the felony, the negligence would have to be GROSS negligence - a higher burden.
Gross negligence involves more than ordinary carelessness,
inattention, or mistake in judgment. A person acts with gross
negligence when:
1. He or she acts in a reckless way that creates a high risk of
death or great bodily injury;
AND
2. A reasonable person would have known that acting in that
way would create such a risk.
It is element number 4 - the causing of death - that will be tough.
[An act causes death if the death is the direct, natural, and
probable consequence of the act and the death would not have
happened without the act. A natural and probable consequence is
one that a reasonable person would know is likely to happen if
nothing unusual intervenes. In deciding whether a consequence is
natural and probable, consider all of the circumstances established
by the evidence.]
[There may be more than one cause of death. An act causes death
only if it is a substantial factor in causing the death. A substantial
factor is more than a trivial or remote factor. However, it does not
need to be the only factor that causes the death.]
Proving death by speed at such high speeds is no easy task. The defense can likely present an argument for reasonable doubt by presenting evidence of fatal collisions at 55 MPH under similar circumstances (broadside with no seatbelts).
A big issue will be whether the victim vehicle stopped and yielded as required by law. If the victim was not required to yield, then the issue of speed being the cause of the collision and the death becomes stronger.
I have been the primary investigator in a few of these cases, and they always hinge on arguments regarding speed and whether it was sufficient to have caused death.