Your link states that "The autobahn is 27 inches thick", and I've seen 68 cm in other sources, so I beleive that is correct. However it incorrectly states that the "United States freeway system ... is 11 inches thick". According to this source
the concrete is 11" thick, and the subbase is 21, for a total of 32". It's been a long while since I worked on interstate road design (asphalt pavements), but as I recall the constructed thickness was at least that.
There is no question that German super-highways are smoother than their US equivalent. Ireland's roads were too when I drove there about three years ago. I'm not sure why that is; my guess is quality control. Some of the newly constructed roads here are not smooth at all.
There is no question that German drivers are better trained and disciplined than they are here in the US. I'm sure we could fill this thread with 5000 pages of examples of left lane hogs, crappy equipment, distracted and rude drivers. But all that is "fixable", especially in a state like Texas.
from 1999 talking about Michigan
"Europeans generally dig the road about 3 feet deep, compared with only 18 inches in Michigan. That gives the road more support and a better foundation. In addition, European roads are paved with a better grade of concrete.
As a result, European pavement tends to hold up longer and require less maintenance. Unlike Michigan's roads, European roads' deeper base and more durable concrete prevent water from seeping into the pavement, which causes potholes and cracks to form.
``Instead of spending all the attention on the road's surface, Europeans are obsessed with making sure the road has a good foundation,'"
This is consistent with the other contention I've read that the Germans built the autobahn first, then got the cars whereas the in the US the US had the cars and no Interstate system.
``In the U.S., it's acceptable to let the roads be patched up, where in Europe, it's not an option,'' Jacob said. ``They resurface a road in five years regardless if it has holes. Their road standards are well above our minimum standards.''
That about says it all. It also appears to be two layers of concrete while the US one layer. http://www.worldhighways.com/categor...crete-surface/
Regardless, R&P will likely not be returning to the US. Its mostly the safety and people issues. By 1959, R&P was done to NV only. Drunk driving was about as important as a red light ticket. Cars were death traps. There was no distracted driving. And the alcohol limit was .15. Today, never going to happen because of safety mandates and people problems. People are people. They will drive at 110 while talking on the phone.
You know 911s never had cupholder? You don't drink or eat anything while driving. There is a famous story on reddit where the PCNA had to tell Stuttgart to put cupholders in the Cayenne. Take a look at the cupholders in a 911 or the boxster, complete afterthoughts. Spill a drink, hit a bump and liquid is all over the console. You are not supposed to be using them. Drivers drive, not drink coffee. Its a different world. And with deaths per VMT increasing, likely because of not using seat belts and cell phones, I wouldn't hold my breath.