Two people were injured and a driver has been arrested for DUI after a chain-reaction crash sent a car off I-5 in South Seattle Wednesday evening. A van was heading south near Airport Way just after 6 p.m. when it suddenly hit the brakes, according to Trooper Rick Johnson with the Washington State Patrol. A driver of an Infiniti swerved to avoid the van. The Infiniti driver then hit a Dodge Charger, which sent that car off the freeway where it rolled over and landed on its roof on Airport Way below. A 17-year-old boy and 18-year-old man in the Charger were taken to Harborview Medical Center where they were listed with stable vital signs. A third person in the charger -- another 18-year-old man -- wasn't injured. Troopers are still investigating the circumstances around the crash. One of the drivers has been arrested for investigation of driving while impaired with drugs, but Johnson didn't have the details yet of which driver it was.