Several drivers in Lancashire have been punished for not knowing the Highway Code rules on lane hogging, police said.
Lancashire Road Police took action this weekend, pulling over cars after bank holiday traffic was "made worse by the MANY motorists who don't observe lane discipline".
In a tweet on Monday evening, the force posted an edited motorway road sign explaining the rules.
"Out of all the motorists stopped," the tweet said, "NONE were aware of the Highway Code rule 264".
Police said they gave several "TORs" (Traffic Offence Reports) to drivers, forcing them to take a driver training course or face a fine.
What is "middle lane hogging"?
- Drivers who sit in the middle lane of the motorway when the left-hand lane is clear are often called "lane hoggers".
- To avoid illegally undertaking them, drivers in the left-hand lane are forced into the right-hand lane to overtake lane hoggers.
- At busy times, lane hoggers can unwittingly cause congestion, as three lanes of traffic are squeezed into the right-hand lane to overtake them.
- While lane hoggers might be oblivious to the chaos they cause, they are ranked by UK drivers as one of the most annoying aspects of motorway driving.