In his long career as an engineer and transportation administrator, Thomas D. Larson brought professionalism to everything from potholes to policy.

Mr. Larson, former PennDOT secretary and federal highway administrator, died Thursday in State College. He was 77. His family believes he died of complications from a head injury suffered in October 2004.

Born near Philipsburg, Centre County, Mr. Larson attended Penn State University, where he earned bachelor's, master's and doctoral degrees in civil engineering.

After serving in the Navy Civil Engineering Corps, he returned to Penn State as a professor and administrator.

In 1968, he founded what is now known as the Pennsylvania Transportation Institute at Penn State. Two years later, he helped establish the Pennsylvania Department of Transportation, which he was tapped to head by Gov. Dick Thornburgh in 1979.

Mr. Larson inherited an agency that had been mired in scandal and fiscal irresponsibility. In eight years there, he drastically improved PennDOT's reputation and balance sheet, in part by centralizing control over state highway maintenance and securing federal highway aid.

"He became known as a guy who was not only an innovator but well respected nationally, whereas the department was almost the opposite," said Allen Biehler, current secretary of PennDOT. "The directors since have almost felt a responsibility ... it's a legacy of Tom's that everyone tries to protect."

In 1989, Mr. Larson was chosen by President George H.W. Bush to head the Federal Highway Administration. In that role, he shaped the Intermodal Surface Transportation Efficiency Act of 1991.

After four years in Washington, D.C., he moved to Lemont, Centre County, and started a consulting business. Since 1993, he also served on the board of the Moon-based Michael Baker Corp.

Survivors include his wife of 50 years, Esther; three daughters, Catherine Bisbee, Suzanne Fetter and Marilee Peery; and eight grandchildren.

The funeral was yesterday in State College.