Edward B. Layne Jr., 52, the managing partner of a Rockville law firm and a former president of the Montgomery County Bar Association, was killed early Friday in a traffic accident on Interstate 95 near Elkridge, Md.

Maryland State Police said Mr. Layne, who was traveling alone, was southbound on the highway when he apparently fell asleep at the wheel and struck the back of a flat-bed truck. He was pronounced dead at the scene of the accident.

A native of Lynchburg, Va., Mr. Layne grew up there and in Washington. He graduated from Woodrow Wilson High School and earned bachelor's and law degrees at the University of Maryland.

After service in the Marine Corps, he joined the State Farm Insurance Company as a claims adjustor. He was admitted to the District of Columbia and Maryland bars and then became an attorney for State Farm.

In 1963, Mr. Layne joined the law firm of McInerney, Latham and Layne in Rockville. In 1970, he was named managing partner of the firm, which recently became McInerney, Layne and Rice.

Mr. Layne was president of the Montgomery County Bar Association in 1976 and 1977. He also was a member of the Maryland State and American bar associations and the American College of Trial Lawyers. He was a cofounder of the Counselors Club.

Survivors include his wife, the former Katherine Kuehl, of Rockville; three daughters, Jeanette Layne Flickinger of Gaithersburg and Martha Kuehl and Diane Sattre Layne, both of Rockville; and one sister, Nancy Layne Albin of Farmington, Mich.

The family suggests that expressions of sympathy be in the form of contributions to Children's Hospital National Medical Center, Washington, D.C.