Lambton OPP are investigating reports of debris being thrown at moving traffic along Highway 402.
Several complaints were made to police around 11:15 p.m. Sunday, after items were tossed at vehicles from the Murphy Road overpass.
Cst. Jamie Bydeley said items included metal pipes and garbage. He said three vehicles were damaged.
"Thankfully there were no injuries," said Bydeley. "Obviously this is a very dangerous situation for motorists and anyone with information is asked to contact Lambton OPP, or if they see these events going on, typically late at night, they can dial 911."
Cst. Bydeley said there were also calls about someone running across the highway, placing items on the road.
"That was all involved with the complaints that different items were strewn across the highway," he said. "We had reports that some black pipe, like drainage pipe, was put across the highway so we had to engage the MTO in order to remove debris while officers were making their way."
He said these are very serious offences, and currently there are no suspects.
"If someone were to lose their life, which is entirely possible, throwing large objects at vehicles travelling at those speeds," he said. "If someone were to die as a result of doing this, they could be facing manslaughter charges."
Anyone with information is asked to call Lambton OPP at 1-888-310-1122 or Sarnia-Lambton Crime Stoppers at 1-800-222-TIPS (8477).