Crashes of two cars following a diesel-fuel spill closed the southbound ramp from I-80 onto I-15 Monday morning, and all I-80 traffic was diverted north onto I-15 for more than an hour. Two men and a woman suffered minor injuries in the 9:40 a.m. accident, said Utah Highway Patrol Sgt. Ted A. McGregor. A ruptured fuel tank on a gravel truck was apparently responsible for the spilled fuel, which slickened the concrete roadway for more than 150 yards, McGregor said. The woman's car was the first to hit the spilled fuel, causing her to strike the guardrail. The second car avoided the first vehicle but bounced off both guard rails before the front became wedged against the barrier on the south side of the ramp. UHP troopers stopped a gravel truck believed responsible for the spill several miles away on I-15.