Drivers who hog the middle lane or tailgate other cars now risk an on-the-spot fine and three points on their licence under plans unveiled by the government.
The plans also include a rise from £60 to £100 in the fine for using a mobile phone while at the wheel.
The fixed penalty of £100 will also enable police to offer educational training as an alternative to licence endorsement.
Stephen Hammon, road safety minister, said: “Careless drivers are a menace and their negligence puts innocent people’s lives at risk.
“That is why we are allowing the police to immediately issue a fixed penalty notice .”