A McDonald man pleaded guilty yesterday to homicide by vehicle in a fatal accident on Interstate 79 last year in which both cars were going 100 mph.

Robert F. Macartie, 24, was going about 105 mph on I-79 in Collier late on Oct. 20, 2007, according to a police affidavit, when he struck another car, then hit a car driven by Chad R. Barber, 33, of Mount Washington.

Mr. Barber's car, which was traveling 100 mph, ran into a guardrail and flipped several times, according to the affidavit. Mr. Barber was pronounced dead at St. Clair Hospital.

The woman in the first car Mr. Macartie hit suffered minor injuries.

In exchange for the guilty plea, prosecutors withdrew the most serious charge of homicide by vehicle while under the influence of alcohol or drugs. Mr. Macartie also pleaded guilty to involuntary manslaughter, reckless endangerment and DUI. His blood alcohol level was 0.139, according to the affidavit, A driver registering 0.08 is legally drunk.

Mr. Macartie will be sentenced April 2 by Common Pleas Judge Anthony M. Mariani.