I am not sure if you can help me with this or if you can tell me who I can ask to get my answer.
I know that for many years in the Washington DC area from the time DC streets where first made all city streets where Cobblestone and I am trying to find out when they were changed over to cement streets as they are now.
I know that when the DC streets were formed all streets were cobblestone then sometime (I assume) they were changed over,  I am trying to find when they were changed.  I assume that it took many decades to change them all. I guess they were changed as paved streets are easier to drive on.
So I am trying to find out when they were changed and what was the process to do them all was.  I assume they weren't all done at the same time. 
Do you think you could find me some data of when, and what part of the city was done at what time.  I know I might have to do a little digging and asking around but any help and insight into it would be good.
I do know some historic preservation group have saved a street or two from being paved over but what the street is and how they did it, I am not sure.
Any dates of when the streets went from Cobblestone to paved Streets I would love know about it.
Please do let me know what you can find for me.
Stephen Hosmer