How did economic development during the Gilded Age affect urban residential patterns?

The main way in which economic development affected urban
residential patterns was by contributing to the beginnings of what we would now call
"sprawl."  Economic development (along with technological developments) created a large
new middle class that could move out of the inner cities and into new
suburbs.

As the Gilded Age brought in more large companies
and more of a need for white collar employees, the size of the middle class increased. 
At the same time, innovations in mass transit such as the development of electric
trolleys allowed the middle class to move away from the inner cities and out into the
"streetcar suburbs."