This is not selfishness, I live on the other side of the country where there's no chance in hell of ever getting speed limits raised to 90mph. Nor do I think they should be. Rather, I think highway speeds ought to be 80th percentile. But I have spent lots of time in cars in NV and Utah and NM as a passenger and frankly it seems that the biggest problem out there is simple highway hypnosis. It's a long $#@^ way between anything in those states. Shorter travel time can be a huge win.
Anyway, you are wrong about tighter speed limits, but that's probably because you have not looked at the literature.
What has been shown time and again is that reducing the speed differential between traffic reduces accidents and fatalities, independent of actual speed. Your chances of dying in a crash are higher if you're going faster, but if you can reduce the incidence of crashes it can be -- and is -- a net win. So the goal here is to reduce accident rates as much as possible.
The engineers say that the way to do this is the 80th percentile rule; you let traffic free-flow and watch how fast it goes. Set the speed limit to the 80th percentile, rounded up a little (5mph in the US, 10k elsewhere). Set minimums at 10mph (20kph) lower.
The statistics say that traffic travelling 10mph faster *or* slower than average sees accident rates climb to 300% normal. Moreover, the slower side sees multi-vehicle accident rates climb 900%! Slower drivers cause a lot of accidents, and they involve other people much more often.
Now let's put that into the context of a typical 55mph US highway. Average traffic speed is 67mph on those highways. Minimum limits are 45mph. That means that someone -- legally -- going at the lower limit is actually going more than 20mph too slow! Very, very dangerous, both to themselves and to everyone else. But someone going 70mph -- 15mph too high according to the law -- is statistically very safe.
Given these numbers typical interstate traffic speed limits should be 70 or 75mph, not 55 or 65mph, and minimums should be 60 or 65mph respectively. That's what the engineering says. We have, unfortunately, eschewed engineering in favor of politics.
So, we have some great data from when the NMSL was repealed and a lot of limits jumped to 65mph. The first really interesting figure is that average traffic speeds jumped -- to 69mph. This put to lie the idea that traffic is just going to run at the tolerance limit of the police regardless of the speed limit. In fact, traffic tends to drive at "comfort" speeds, which unsurprisingly are somewhere near the design speed of the road.
With such a minimal increase in typical speed you wouldn't expect a large change in fatalities. There was a significant change though, absolutely -- but not when normalized for vehicle miles traveled. Moreover the fatality rate for the road system as a whole dropped by something like 5%. It's believed that this is because the change in highway limits made drivers prefer the safer interstates to the less safe rural highways (now 70mph was unlikely to get you a ticket).
Anyway, I spent awhile researching this stuff awhile back and may even still have a bibliography buried in my archives somewhere but I encourage you to do the research yourself. Even Wikipedia mentions this stuff, you could start there.
I note that many of these figures are multinational. The data supports this in the US, the UK, France, and Germany at a minimum. The best studies of this are in France and Germany. (Germany is an odd man out though; the autobahn is pretty safe even though it has severe vehicle speed differences; driver training might have a lot to do with it. US driver training is pathetic, nigh on nonexistent, and I would not recommend autobahn-style laws here.)
Here are a couple of additional factoids for you:
- Average accident speed on non-interstates in the US is 27mph. Average accident speed including interstates is 29mph. What this means is that most accidents do not have speed as a significant factor. This is not actually terribly surprising when you go look at where high accident rates occur. It's not the highways! It's not even close. Which brings us to:
- Fewer than 10% of accidents happen on highways. The US interstate system has the safest roadways in the country by far.
So where are accidents and fatalities happening in large numbers? Surface streets, at intersections. Failure to obey traffic control devices and failure to yield are the two biggest causes. These accidents happen at relatively low speeds, but it turns out that even 30mph is a honking big hunk of energy when you're talking about a couple of two-ton vehicles colliding.
I note that US traffic safety programs target speed almost exclusively, with almost no effort spent on either training or enforcement at intersections. This is unbelievably stupid public policy. The fine structure shows this bias too; speeding fines are large and grow very rapidly, but fines for running a red light tend to be near nominal. The red light runner is far more dangerous.