“Over the years, I’ve done many follow up studies after we raise or lower a speed limit,” Megge tells us. “Almost every time, the 85th percentile speed doesn’t change, or if it does, it’s by about 2 or 3 mph.”
This is consistent with most drivers behaving like _archon_ (and like me). For example, if every driver thinks she can safely drive 90 mph, but 80%, like _archon_ and me, stay below 10 over the limit out of fear of police, while 20% drive as fast as they like, then raising the limit from 60 to 70 will have no effect on the 85th percentile.
The article seems to quietly conflate the fastest 15% of drivers ignoring the limit with "most drivers" ignoring the limit. Which is odd. However, even under the _archon_ model, increasing the limit would lead to a reduction in speed variance.
Had the unique experience of entering into Utah where the highway speed limit was 80mph (~ 130 km) and had no desire to drive any faster than that, it was a very comfortable speed for that road and everyone was going about the same speed so it didn't clog up or get a lot of people changing lanes to adjust.
For a long time in Nevada there were no speed limits (prior to the 55 law) and we'd drive up 395 toward Reno at 80 - 85 mph which was just fine.
It seems like you just have to believe that making a faster limit won't ratchet people to 'limit + 15' where they are when it is 65.
Just as Megge can point to the results on hundreds or thousands of roads which have become more safe or equally safe when the speed limit increased, other researchers looking at data sets of speed limit changes have come to the opposite conclusion and advise that raising speed limits comes with the price of thousands of roadway fatalities.
Although the article seems to support Megge and the studies he likes, it's not clear why (other than maybe that it makes for a more interesting blog post).
And honestly, I can't imagine I'm the only one who feels comfortable going 80 on a 65 MPH highway but not on a 55 MPH highway. I guess it is possible, but it seems hard to believe.
The speed limit drops arbitrarily from 65 to 55 from MA-146 to RI-146 at the state border. Risk of a ticket aside, 80 is fine on either side of that invisible line (long straight flat highway with trees on either side).
Yes, according to that article. What I'm driving at is that making an arbitrary change based on how drivers react to an improper restriction may in fact lead to imposing another improper and arbitrary restriction.
A change of 5 mph either way won't change anything fundamental, and so a traffic study will report minimal changes.
“Over the years, I’ve done many follow up studies after we raise or lower a speed limit,” Megge tells us. “Almost every time, the 85th percentile speed doesn’t change, or if it does, it’s by about 2 or 3 mph.”