OPP Sgt. Kerry Schmidt said the entire highway was initially closed between Mill Street and Newtonville Road as a result of the crash.
Westbound lanes opened around 6 a.m., though eastbound traffic was blocked for several more hours.
As of 5 p.m., only one eastbound lane remained blocked near the crash scene.
The collision happened around 5 a.m. and involved two transport trucks and another commercial straight truck.
Schmidt said one transport truck was disabled on the right shoulder, when a straight truck crashed into it.
Both drivers got out of their vehicles to speak to each other, Schmidt said. A third vehicle, another transport truck, then crashed into the straight truck.
Schmidt said a 40-year-old from Ingersoll, Ont. was pinned between the trucks and died on scene.