A man accused of killing three people in a Daly City drunken driving crash earlier this month pleaded not guilty to three counts of DUI vehicular manslaughter among other charges in San Mateo County Superior Court Tuesday, according to the San Mateo County District Attorney.

Sunnyvale resident Denis Pereria Demacedo, 28, appeared in court Tuesday afternoon following his arrest in the March 9 drunken crash in which Josefa Osorio Acevedo, 50, and her sons Amado Osorio Acevedo, 23, and Josue Osorio, 15, were killed after they were struck on Eastmoor Avenue in Daly City.

Prosecutors allege Demacedo was speeding away from an earlier drunken driving incident.

A fourth passenger, a woman, was severely injured in the crash and remains hospitalized, according to the district attorney's office.

Josefa was a single mother. Her only children were Amado and Josue.

Demacedo was on probation from a 2010 drunk driving conviction, and on the day of the triple-fatal accident had spent the afternoon drinking beer with friends at a Daly City pizzeria before getting behind the wheel at around 8 p.m. that night, prosecutors said.

Before broadsiding the victims' car, Demacedo allegedly reached speeds of up to 60 mph.

A blood test taken two hours later measured his blood-alcohol content at .18 percent, which is more than twice the legal limit, according to the district attorney's office.

He was arrested at the scene and charged with three counts of gross vehicular manslaughter while driving under the influence, felony DUI causing great bodily injury and misdemeanor hit-and-run, according to district attorney's officials.

Demacedo, a native of Brazil, is scheduled to return to court on April 9, according to District Attorney Steve Wagstaffe.

He remains in custody on no bail.