A tractor-trailer driver suffered a medical emergency Tuesday morning, causing him to crash on southbound Interstate 5, about 6 miles north of Vancouver, according to the Washington State Patrol. No one was injured in the crash.Billy Geitl, 62, of Silver Lake was driving a red 2007 Peterbilt tractor-trailer south on I-5, approaching 179th Street, when he experienced a medical event about 11:30 a.m. The tractor-trailer drifted off the road to the right and struck the guardrail. It came to rest on the right shoulder, according to a WSP crash memo.Geitl was transported to PeaceHealth Southwest Medical Center for treatment related to the medical event. He was wearing a seat belt, troopers said.No citations or charges were issued.