Cobblestone roadways are used extensively in Europe. Why are they not used on modern American urban roadways?
When contrasted to the conventional pavement--asphalt, what are the major differences that make all streets paved with asphalt. There are some clear and obvious advantages to asphalt being quick to lay down, cheap to make, and easy to patch. But its disadvantages are clear too, it has relatively short design life (20 years generally iirc) and old asphalt gets patchy, bumpy, and just down right ugly.
Assuming that the cost of the subgrade is comparable between cobble roadways and asphalt roadways why don't we see at least some cobble roadways being built? A common answer to my question is that cobbles aren't nice to drive on but everyone who says that hasn't driven in Paris or other largely cobbled cities. Although I can't offer a decibel rating between the two I can remember having no such thoughts when driving in Europe.
Some advantages that I can see for cobbles over asphalt are that the design life would almost have to be longer than 20 years, or less than 20 years for the same cost of material (assuming the subgrade isn't remade after each repaving of asphalt). If designed right cobbles wouldn't deform like asphalt and when it needs to be patched there isn't an eyesore patch left in the place of the pothole. If it the street needs to be repaved the cobbles can be removed and used on another project. Laying cobbles would be time intensive compared to asphalt but it would require less maintenance. Besides, they are aesthetically attractive to look at.
So let me reiterate my question, why are cobbles never used on modern American roadways?