PennDOT supports nearly 40,000 miles (64,000 km) of state roads and highways, about 25,400 bridges, and new roadway construction with the exception of the Pennsylvania Turnpike Commission.

PennDOT has extensive traffic cameras set up throughout the state's major cities, including Philadelphia, Pittsburgh, Allentown, Erie, Wilkes-Barre, Scranton, and the state capital of Harrisburg, In Wilkes-Barre, cameras are fed through to a television channel for Service Electric cable customers in the city and its suburbs.

Greatest growth in the state highway system occurred in 1931 when 20,156 miles (32,438 km) of rural roads were taken over by the Commonwealth.

These grants continue today and now comprise the key element in determining the size of the state's roadbuilding programs.

State payments to local communities for road maintenance also have continued to expand so that they average approximately $170 million annually.

An effort to bring quality management principles to PennDOT over an extended period—four changes of state governor—accomplished a great deal.

The deputate is made up of over 9,300 employees in design, construction, maintenance, materials testing, environmental review, safety, and traffic engineering.

Transactions relating to motor vehicles, such as vehicle title transfers or replacing a lost registration plate, which would typically be handled by a DMV office in other states, are handled by a network of private businesses called "messenger services", which contract with the department.

It is also in charge of the cash flow from the federal and state governments to fund improvement projects along with working on long-range research and map making.

[6] PennDOT provides the primary funding for two Amtrak trains in Pennsylvania that operate along the Keystone Corridor.

The Keystone Service runs between Harrisburg and New York City via Philadelphia and offers multiple daily departures.

[10] Across the United States, 61,000 bridges are deemed "structurally deficient",[11] which means they need repairs, contain a piece rated as "poor," and might also have a weight limit.

[14] This is partly explained by the freeze-thaw cycle creating potholes, the Karst Topography leading Pennsylvania prone to sinkholes, heavy commercial traffic, and funding issues.