Louis B. Holdeman, 64, a physicist and engineer who had worked since the mid-1990s for the Northrop Grumman Corp. in north Baltimore and for NASA, the National Bureau of Standards and Comsat before that, died Dec. 2 in a Baltimore hospital as a result of injuries he received in an auto accident Nov. 4.

A spokesman for the Maryland State Police said Dr. Holdeman was westbound on Interstate 70 in Baltimore County near Route 695 when his vehicle struck another westbound vehicle that was slowing in traffic. The accident is under investigation.

Dr. Holdeman, who lived in Boyds, was a native of Baton Rouge, La. He was a 1962cum laude graduate of Louisiana State University, where he was a member of Phi Beta Kappa, and received a doctorate in physics from Stanford University. He served in the Marine Corps from 1956 to 1958.

He was a research physicist with NASA in Huntsville, Ala., before coming to the Washington area in the mid-1970s. He then worked as a physicist with the National Bureau of Standards in Gaithersburg and Comsat Laboratories in Clarksburg.

Dr. Holdeman's hobbies included cooking, gardening and maintaining and racing Porsche automobiles. He had been a racing instructor and a member of the Potomac Porsche Club.

His marriage to Nancy Banister Holdeman ended in divorce.

Survivors include two children, Michael Louis Holdeman of Seattle and Karen Holdeman Tellez of San Antonio; his mother, Dorris Norton Holdeman of Baton Rouge; two brothers; a sister; and two grandsons.