A man whose pickup truck smashed into a police cruiser in July, killing a Maryland Transportation Authority officer, was arrested yesterday and charged with negligent homicide and other offenses.

In announcing the charges, authorities said Albert G. Antonelli was speeding and tested positive for cocaine and diazepam, the generic version of the anti-anxiety drug Valium.

An indictment also charges him with possession of cocaine and marijuana.

Antonelli, 32, of Queenstown, Md., struck the cruiser on the morning of July 20 on Route 50 in Anne Arundel County, authorities said. The officer, Cpl. Duke G. Aaron III, 29, had just issued a ticket, and his unmarked cruiser was parked on the side of the road's westbound lanes -- near the Chesapeake Bay Bridge -- when Antonelli's 1998 Dodge Ram rear-ended it.

Aaron died that afternoon of injuries he received in the accident. The Pasadena resident, who had won his department's officer of the year award three times, was remembered at his funeral as a dedicated husband and officer.

An Anne Arundel grand jury issued a 12-count indictment against Antonelli yesterday, charging him with seven criminal offenses and five traffic offenses.

Kristin Riggin, a spokeswoman for State's Attorney Frank R. Weathersbee, said blood tests showed that Antonelli was using cocaine and diazepam. According to the indictment, he was driving faster than 73 mph in a 55-mph zone.

Police have said previously that Antonelli was driving with a suspended license when the crash occurred.

Antonelli's attorney, Andrew White, did not immediately return calls last night.

Riggin said the period between the crash and the indictment was typical of such cases.

She said such cases "usually take a considerable amount of time due to the level of investigation that must occur, including accident reconstruction, blood testing and other factors."

Catherine Leahan, spokeswoman for the transportation authority, said Chief Gary McLhinney and all of the officers at the agency, which investigated the crash, were pleased with the charges. "We have complete confidence in our report and in the justice system," Leahan said.

"The family needs closure, and we hope that this person pays for what he did for a long, long time."

Riggin said Antonelli was arrested at his residence.

No trial date has been set.