I don't think it will, though - the data I have read says it will have little to no effect, and actually could have a negative effect. Most residential limits are already abnormally low in terms of safety from a traffic engineering perspective.
http://safety.fhwa.dot.gov/speedmgt/ref_mats/fhwasa1304/Reso...
> There's about a 17% risk of death if you're hit by a car going 30 mph, vs 12% at 25 mph.
That's why I brought up the effectiveness of change in posted speed.
So it would probably save lives, and while 1 or 2% doesn't seem like much, the parents of those childs would beg to differ.
Not sure if an appeal to emotion is going to work too well on HN. While I certainly sympathize with those parents this is the absolute wrong way to go about implementing policy or law. Most of US law that has eroded our rights over the years has been enacted by similar emotional arguments. I prefer my policymakers to be sober dispassionate people who look at raw data to make as an informed decision as possible.
Killing a human being is not the same as killing a process. We live in a society because it's safer. We have a constitution, rights, and laws to protect us (at least in theory). The optimal law would save as many lives as possible. I don't see how saving lives makes a poor heuristic for implementing laws.
If that were true, cars would be illegal.
We're operating in a framework of likely accidents, benefit to society and overall cost. There is an optimal law that saves as many laws as reasonably possible, and in most cases it has already been implemented and is being enforced. Where it has not or is not, sure.
The driver was doing 40 in a 30 (mph) and was on his cell phone.
I still don't think every traffic law should be modified to prevent this scenario.
It's silly to emotionally invest in the law. Preventing all traffic deaths is just not realistic currently.