EL CAJON, Calif. -- A young man accused of driving a BMW at speeds up to 100 mph before slamming into a pickup truck, killing a newspaper carrier on her pre-dawn rounds, pleaded not guilty Wednesday to a vehicular manslaughter charge.

Jonathan Dallo, 19, of Jamul, faces up to six years in state prison if convicted of the charge, which carries an allegation of gross negligence, Deputy District Attorney Terrie Roberts said outside court.

"There were no alcohol or drugs involved, just speeding," the prosecutor said.

The crash occurred last Wednesday when Dallo swerved out of an eastbound lane on State Route 94 in Jamul to pass slower traffic about 4 a.m., authorities said.

The 2003-model BMW crashed into a Ford F-150 whose driver, San Diego Union-Tribune employee Jodi Burnett, had stopped to make a left turn onto Rancho Miguel Road.

The impact knocked the truck over onto the driver's side, partially ejecting Burnett, who died at the scene.

The 40-year-old Spring Valley mother was not wearing a seat belt at the time of the accident. Newspaper delivery workers are legally exempt from safety-restraint requirements.

Officers arrested Dallo, who was uninjured, and took him to county jail.

At least one witness in another vehicle said the defendant had been traveling at upwards of 100 mph just prior to the fatal wreck, Roberts said.

Superior Court Judge Laura Halgren, who allowed Dallo to remain free on $50,000 bail, scheduled a readiness conference for Aug. 11 and a preliminary hearing for Sept. 12.