A Nassau police officer remains in critical condition after an accident involving a drunken driver forced him to undergo brain surgery.

Officials say Officer Kenneth Baribault was writing a ticket in his patrol car for Marcin Bykuc, a suspected drunken driver around 6 a.m. Sunday near exit 46 on the Long Island Expressway. According to officials, Officer Baribault was hit when 27-year-old Rahiem Griffin slammed into the police cruiser, propelling it into the car that was stopped.Officer Baribault was taken to Nassau University Medical Center, where doctors operated on his brain due to a blood clot. Officials say doctors also removed a portion of his skull to allow for swelling. Doctors say they are optimistic about Baribault?s progress since he began physically responding to people?s voices Monday.

Baribault?s family is thanking the off-duty New York City firefighter who ran across six lanes of highway to help the officer. Authorities say Philip Scarfi removed Baribault from the car, initiated rescue breathing and used the police radio to call for help.

Bykuc was arraigned Monday in Hempstead. Griffin is facing charges of vehicular assault, reckless driving and DUI. Police say Griffin had his New York driver?s license suspended, but was able to get one in New Jersey by changing his name.

Click for more on the firefighter who helped rescue Baribault

Off-duty fireman saves Nassau cop in horrific LIE crash