The QEW was closed both directions between Fruitland Road and Centennial Parkway for nearly five hours Thursday morning.
OPP Sgt. Kerry Schmidt says a tractor trailer lost control around 5 a.m., went into a ditch, and took out several power lines.
Those lines were left hanging low across the highway.
Schmidt says there were reports of another vehicle driving aggressively in the area at the time.
Police are asking witnesses to come forward.
All lanes reopened just before 9:30 a.m.