I've seen this pattern in a number of "unintuitive and seemingly clever" traffic engineering tricks proposed in recent years. For example, it has been shown that removing all traffic signs can in fact improve safety -- again by slowing everyone down.
Another similar point (mentioned in the article) is that expanding freeways doesn't reduce congestion, because the new lanes are filled quickly. The argument is, apparently, that we therefore should not bother expanding freeways. The argument ignores the fact that the expanded freeway is serving many more people, creating immense value even if the speed of traffic hasn't improved.
(For the trolls: I personally take the train rather than drive whenever possible.)
Of course it is good for the economy that people can commute effectively. But by building more lanes we are choosing spread out cities dominated by highways where no one wants to live and instead drive to work from the suburbs.
And there are alternatives. We can choose more densely populated cities where the streets are dominated by pedestrians and people commute shorter distances mostly by public transport. Much better for the environment, and most importantly, better for people.
And we are making that choice whenever we chose between using the land for new roads or using the land for new pedestrian buildings and railways.
Comparing my apartment in Boston to mine in SF is like day and night. Here, I feel like I have my own place. It is a tad bit like a hotel room, but I don't hear much neighbor noise compared to the racket in Russian Hill.
Having a continual uneasiness due to random loud noises or having your own life impacted (listening to TV at a whisper, for example) is not human-friendly.
I think apartments get a bad rap because they are built with paper thin walls. It is more expensive to build with bigger spaces and proper noise control, but it has made a giant difference in my standard of living.
Please don't put out blanket claims like this and pretend they're obviously true, and then use them as justification for your particular view of how society should structure its geography. Some people hate densely populated areas. It would be utterly detrimental to my mental health to live in one. So if I have the choice to not live in an urban area, I'm going to take it.
I have a 45 minute commute each way every day to work. Long commutes suck. Living in the city sucks way more.
If moving from 30mph roads to 20mph roads reduced average traffic speed, then this would be a valid argument.
However, for most urban streets during the daytime the average speed is set not by the roads themselves but by the traffic capacity of the intersections along the road. It doesn't really matter how fast you can drive along a road if it only means that you get to the back of the queue for the next set of traffic lights a little earlier!
I commute-by-bike on a road with bike lanes in Somerville and Cambridge. At rush hour, no matter what the speed limit, the fastest way from point A to point B is a bicycle (unless A and B are stops on the red line), almost never exceeding 20mph. The reason cars are slow is that they take up too much space and have to wait in line, again and again and again.
No, that's simply not true. What actually happens is that media outlets write whatever the hell they feel like will sell, rather than what was in the scientific report. This is far more accurate than your description: http://www.phdcomics.com/comics.php?n=1174
My point is that it's important to through out the telephone game that reports science, rather than the science itself. One shouldn't trust somebody else's summary of a scientific article, it's important to go look for oneself. Since this is a tech website, Peter Norvig should be a familiar name, and he has an excellent example of that here:
This article repeats some conclusions from various research efforts of unknown (to me) quality, most of which carry caveats, and none of which were titled "Effects of Lane Width on Pedestrian Safety: A Quantitative View". These weak (not pejorative, just opposed to strong) statements are then used as the base assumptions atop which a logical argument is constructed - an argument that is incomplete. The relationship between speed and mortality is only attacked from the perspective of what happens once a collision has taken place, for instance, but there will likely also be a relationship between speed and the level of caution exercised by pedestrians, but no evidence about this is presented.
This is a question in need of comprehensive study; the tidbits presented here are neither strong nor complete enough to say anything absolute, much less accuse anyone of having blood on their hands.
Personally, I think such a study would validate much of what the author feels. But it is only my gut that says that, I'd need a study to "know". As such this comment is not meant as a criticism of the author or the thoughts in the article, but more as a sort-of defensive reminder of what the scientific method means.