During Colonial times private citizens maintained certain roads and expected to be compensated. After the creation of The United States, the government decided to use their resources to maintain the roads for the fair use of all. This concept of tolls was used in the creation of new highways. The theory was to eliminate the tolls once the cost of the new highway was paid for. Guess what! This system became a money maker. The idea was to use this money to fund other government programs. The true accounting is mired in buracrecy.

Population and continued road construction to keep pace with americas automobiles. if a special expressway is built, within a state by that state, to specifically connect one city with another, its called a toll road. in other words, this is a state-funded highway without federal assistance. and, the users of this highway, for the convenience, will pay a small toll till the highway is completely paid. inital funding may come from private and/or public monies. the toll fees go to paying this debt.

Though there are more toll roads or turnpikes on the east coast and northern states, I don't believe there's a particular reason, other than that the road systems have been there longer. Just as another answerer refers to these roadways in Colonial times and then the US Government continued the idea. This is just part of what you'll find on Wikipedia.com about toll roads: A toll road in the United States, especially near the east coast, is often called a turnpike. The term turnpike originated from the turnstile or gate which blocked passage until the fare was paid at a toll house (or toll booth in current terminology). Some states have a RF tag that automatically bills the commuters account electronically for tolls. Examples of this are the E-ZPass electronic toll collection system used on most toll bridges and toll roads in the eastern U.S. from Virginia to Maine, and recently extended into Illinois; Houston's EZ Tag, which also works in other parts of the state of Texas, California's FasTrak, and Florida's SunPass. Traffic in these special lanes can move well with minimal slowing. Toll roads are only in 26 states as of 2006. The majority of states without any turnpikes are in the West and South. Here's their link: http://en.wikipedia.org/wiki/Toll_road