I think there is another interesting angle here: while a death of a person from a car driving too fast is a horrible tragedy; for the society as a whole, it might be better to accept X deaths to get Y people to their destinations faster. This is a common mistake in the modern political practice to use one-time/rare events to justify stricter laws for everyone. Most obvious and well known recent example, of course, is the establishment of TSA after 9/11. But the same applies to the speed limits on the road: a one-time car crash is usually used to justify lower speed limits.
You make a good point, but let's not pretend that crashes due to speed are "one-time" events. There is a certain roadway near where I live that frequently has these types of crashes. Lowering the speed limit doesn't help of course (these people are interested in obeying any posted limit).
I was talking about situations when a single crash on in a particular place of the road causes the speed limit to be dropped. I have no problem with lowering speed limits or doing other changes to the road when there is a history of incidents. E.g. I think police & other agencies did a fantastic job on hwy 17 a few years back to make it much safer and more pleasant to drive.
