even in this dream world where we've made those changes, I don't think it's unreasonable to assume we will still find places in which if drivers tend to exceed a certain speed, there comes a higher likelihood of said harmBut the question is not whether people's behavior affects the likelihood of harm; of course it does, in all areas of life, not just driving. The question is what is the appropriate response. See below.
And if someone is putting others at risk by violating this, it comes down to a question of how you respond to that, and I at least would pen a reasonable solution at trying to proactively influence their behavior patterns
And you do that, IMO, by attaching punishments to actual harm, not to an increased likelihood of harm (which must always be an estimate only).
First of all, the legislator who drafts the speeding laws and the bureaucrat who sets the speed limits for particular roads can't possibly know as much as the driver who's actually on the spot about what a reasonably safe speed is in a particular situation; speeding laws can't adjust for varying conditions.
Second, if punishments are attached to actual harm, and fall on the person who causes the harm, then that person has an incentive to make accurate estimates of the risk of harm. The legislator and the bureaucrat have no such incentive; but if the law can only impose punishment when there has been actual harm, the legislator and the bureaucrat can only do a limited amount of damage by trying to game the criteria.
However, if punishments can be attached to just an estimated increase in risk of harm, rather than to actual harm, legislators and bureaucrats have an incentive to exaggerate the estimated risk of harm, since it allows them to lower the threshold for penalties and thereby bring in more revenue. But drivers themselves, who can see perfectly well that the criteria are being gamed, respond by trying to evade the law. The end result is that the costs of the system that is in place to catch speeders, and the escalating arms race between the speeders and the government, far outweigh any benefits that might accrue from imposing punishments when there has been no actual harm.