The driver of the van involved in a triple fatality Pinto accident disputed a key claim by Ford Motor Co. Monday that the van was traveling 50 miles per hour faster than the car.

Robert Duggar, 22, currently a college student living in Saginaw, Mich., testified that his van was traveling 50 mph, while the Pinto was moving "about 15 to 20 miles per hour."

The difference in the vehicles' speed could be crucial to the case. Ford is attempting to show the crash impact was so great that no subcompact car could have survived without leaking fuel.

Ford was charged with reckless homicide after three teen-age girls were burned to death when their 1973 Pinto exploded on an Indiana highway in August 1978. The state charges Ford knew early-model Pintos were prone to fires in rear-end collisions but did nothing to correct the defect or warn the public.

Duggar, who spoke softly and hesitated as he recounted the crash, admitted to a long record of driving violations. He acknowledged that his license was suspended until about one month before the accident.

On cross-examination, Ford lawyer James F. Neal said Duggar had only "one-sixth of a second" to judge the Pinto's speed after he returned his eyes to the road and slammed into the car.

Duggar said he took his eyes off the road to look for a cigarette on the floor of the van. When he looked up, he said, "The Pinto was close in front of me . . . about 10 feet."

He said the car was ablaze "within a second."

"I wanted to get out of my van. I thought my van was going to explode, too," he said. "I wanted to help . . .I seen everything was burning, on fire. . . I froze. I just fell to my knees."

The defense tried to discredit Duggar's testimony by reading his driving record and noting that beer, stimulant pills and marijuana were found in his van. Duggar denied he had used the drugs or beer the day of the crash.