The westbound 401 near Summerstown is now open.
Stormont, Dundas & Glengarry Ontario Provincial Police officers are investigating a multi-vehicle collision on Highway 401, between Summerstown and McConnell Avenue exit, in South Glengarry Township.
Shortly before 6 a.m., multiple tractor trailers left the roadway and entered the median westbound on Highway 401. Two passenger vehicles also left the roadway in the same area.
There are no reported injuries.
SD&G OPP, assisted by local tow companies continue to process the scene to remove vehicles.
Highway 401 is closed to westbound traffic with indicated detours in place. Re-opening time unknown.