The only passenger who survived the wreck of a pickup truck last April that fatally injured 10 others admitted in court today that he lied when he told police the truck was only going 30 miles an hour and he hadn't seen its driver drinking beer or smoking marijuana.

The passenger, Kenneth Sassamon, 17, had been riding in the bed of the silver Ford Courier pickup truck just behind its driver, Alan Cole, 19, who went on trial in Circuit Court here today on 26 counts including manslaughter, homicide with a vehicle and driving while intoxicated.

The truck went off rural Patuxent Road in Anne Arundel County about 9:30 p.m., April 23, glanced off two trees, slammed into a third and overturned.

Sassaman and Cole were the sole survivors of the dozen youths who were in the tuck cab and its bed driving to party at a favorite hideaway known as the Pond.

Sassaman testified that contrary to what he told police after the accident he had seen Cole drinking beer between 6 and 7 p.m. and smoking marijuana between 8 and 9 p.m. and that Cole stopped for two six-packs of beer shortly after 9 p.m. as the group set out for the Pond.

Then, he said, "I could feel the acceleration of the truck. The engine was a steady hum, then it started to rev up. I could feel the wind get stronger. We'd go around corners and slide into the other lane."

At one point, all four wheels of the truck left the road, he said.

Sassaman explained his original story to police by saying that Cole "was a friend. I wanted to help him out. It's only human nature."

Assistant State's Attorney Scott Patterson called the trial "a naturally tragic case' and argued that Cole had been grossly negligent the night his vehicle left the road.

Defense attorney Stanley S. Cohen urged the jury to carefully weigh the concept of negligence. "I'm not trying to downgrade the tragedy," he declared. "I've never particiapted in a case as serious as this. Although what [Cole] did may have been negligent and wrong, it's not the kind of negligence that amounts to malicious and wanton disregard for life."

His attorneys filed a motion to dismiss the case on ground that pretrial publicity made it impossible to get a fair trial.

Last month the National Transportation Safety Board concluded that the accident was a result of "reckless driving under the influence of alcohol and marijuana."

"The press did a good job on this case," said Mark Snyder, one of the defense attorneys. "The damage is already done as far as we're concerned."

Circuit Judge Samuel W. Barrick denied the motion to dismiss the case.