EL CAJON, Calif. -- A 75-year-old man who was allegedly drunk when he crashed his SUV into a Carl's Jr. restaurant in El Cajon, killing a diner, pleaded not guilty Tuesday to DUI and gross vehicular manslaughter charges.

Richard Alfred Daus also faces sentence-enhancing allegations that he drove with a blood-alcohol level of .15 percent or higher and caused great bodily injury to the victim.

The defendant -- who has a 1988 DUI conviction in Alaska and a 1952 reckless homicide conviction in Cook County, Ill. -- faces 15 years to life in prison if convicted in the Jan. 3 death of Randy Eugene Smith, said prosecutor Karl Husoe.

Smith, 66, was thrown out of his seat and 35-40 feet across the restaurant when the defendant's SUV crashed into a corner of the building, authorities said.

Smith's chest was crushed and his left leg nearly torn off below the knee, authorities testified during Daus' preliminary hearing last month at the El Cajon Courthouse. The victim, said to be a regular at the restaurant, died on the spot.

Craig Burger testified that he was sitting in his truck near the restaurant on North Second Avenue when he heard a noise and saw an SUV speeding through the parking lot.

"I thought, this guy's going to hit somebody," the witness testified.

Burger said he started calling 911 as the SUV crashed into the eatery.

El Cajon police Officer Jarred Slocum testified that Daus had an obvious odor of alcohol on his breath and slurred speech when he saw him at a hospital two hours after the crash.

Slocum told defense attorney Dan Bacal that Daus was unaware he had been in a crash.

Daus' blood-alcohol level was measured at .22 percent -- nearly three times the legal limit for driving -- when tested at the hospital, said Marissa Ochoa, a criminalist at the sheriff's crime lab.

Video from a nearby Union Bank shows Daus trying to maneuver his vehicle to use a drive-thru ATM, then suddenly taking off across the parking lot and striking the corner of the restaurant.

El Cajon police Detective Timothy Roberts said Daus did not brake as the vehicle traveled the 361 feet across the lot.

The detective said the SUV's average speed as it shot straight ahead toward the restaurant was 33 mph.

An inspection of Daus' vehicle showed nothing wrong with it, Roberts testified.

Roberts said Daus may have swerved to his left just before striking the building.

Bacal argued unsuccessfully that his client's actions during the three to five seconds it took to race across the parking lot amount to simple, not gross, negligence.

The defense attorney something must have happened -- like a medical condition or another malady -- to cause Daus to drive out of control.

Daus will be back in court May 18 for a readiness conference. Hs trial was set for June 1.