The Sûreté du Québec says a truck driver was caught on camera performing a U-turn on the Jacques Cartier Bridge on Wednesday morning.
It happened at around 9: 35 at the exit for the Parc Jean-Drapeau.
The semi-truck was heading towards Montreal from the south shore when the driver started the manoeuvre, briefly blocking all five lanes of traffic.
The driver has since been tracked down.
Police say the manoeuvre could have resulted in a collision.
This type of offence can lead to a $1,546 fine for reckless driving and four demerit points.
Police said the road was open to traffic at the time of the offence.