It was 16 years ago on September 3, 1999, that 87 vehicles collided in dense fog near Manning Rd. on Hwy. 401.
Eight people died and 45 others were injured.
Police remind motorists front and rear vehicle lights should be on in dense fog and four-way flashers can be used if travelling below the speed limit.
Drivers are also advised to leave extra distance between vehicles, reduce speed, and ensure vehicles are equipped with good windshield wipers and washer fluid.