VIDEO: The I-5 express lanes through Seattle are closed following a semi-truck crash around 11 a.m. The semi collided with a tree that is now blocking the Mercer Street ramp to northbound I-5, according to the Washington State Department of Transportation. The truck is at least partially off the road and hanging over the ramp as well, according to Washington State Patrol. The Seattle Department of Transportation is mitigating a fuel leak.