Police say they are hoping to identify a male who threw a road sign onto the QEW in Oakville after a video of the incident started circulating on social media.
Halton regional police say the sign was thrown off the Winston Churchill Boulevard overpass onto the eastbound lanes of the QEW.
Video of the incident shows a young man throwing an orange sign off the bridge onto the lanes below.
Investigators are still trying to determine when the incident occurred.
No injuries were reported, but police describe the incident as extremely dangerous and criminal in nature.
Police are asking witnesses or anyone with information to come forward.