A flipped tractor-trailer closed a busy off-ramp of Highway 401 early Tuesday morning. 

The transport truck rolled onto its side in the westbound lanes near Milton shortly before 3 a.m., according to posts by Ontario Provincial Police on Twitter. 

When crews arrived to move the trailer from the roadway, the top panel became separated, spilling some of the truck's load into a ditch. 

The westbound off-ramp to James Snow Parkway is closed to traffic. OPP could not say when it will reopen.

Crews are at the scene cleaning up debris scattered during the crash.