Lloyd A. Rivard, 52, a former highway planner with the D. C. and federal governments, died Thursday at Arlington Hospital of complications following heart surgery.

Mr. Rivard was a staff member and chief engineer of the Public Works Committee of the House of Representatives for 10 years before retiring in December.

Secretary of Transportation Brock Adams said that Mr. Rivard "was a key figure in the development of our nation's modern transportation system."

House Public Works Chairman Rep. Harold T. Johnson (D-Calif.) hailed Mr. Rivard as "the complete House staff professional on whose depth of knowledge, judgment and integrity members of Congress could rely without question."

Mr. Rivard served as chief engineer in the D. C. Highways and Traffic Department's office of planning and programming from 1966 until joining the staff of the Public Works Committee.

He joined the D. C. department in 1954 as a project development engineer. Five years later he was named assistant chief engineer in the department's office of planning and programming. He left the department for a time in 1962.

A proponent of highway expansion, Mr. Rivard played a major role in the development of plans for the Inner Loop Freeway System. The project has not been built.

He also helped plan the Theodore Roosevelt Bridge, the Anacostia Freeway, and Military Road across Rock Creek Park.

Mr. Rivard strongly favored the construction of Three Sisters Bridge to span the Potomac between Key and Chain bridges, and fought for its construction in the late 1960s and early 1970s. The plans were canceled after a lengthy controversy.

From 1962 to 1966, Mr. Rivard worked as planning and programming engineer with the Automotive Safety Foundation. He helped conduct a study on freeway planning and development in 20 major U.S. cities.

He also worked on freeway studies for the Federal City Council of the District of Columbia during the mid-1960s.

Mr. Rivard was born in North Swansea, Mass., and was a 1949 graduate of Brown University, where he earned a bachelor's degree in engineering. He served in the Navy from 1945 to 1946.

He came to Washington after his college graduation and worked for the U.S. Bureau of Public Roads until 1954.

Mr. Rivard was a member of the transportation research board of the National Academies of Sciences and Engineering.

Survivors include his wife, Beverly G., and a son, Richard L., both of the home in Alexandria; two daughters, Patricia R. Eckley of Gaithersburg, and Lorraine Rivard of Alexandria, and one grandchild.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Fund, or the Northern Virginia Heart Association. CAPTION: Picture, LLOYD A. RIVARD