Anyone ignoring the rules faces a 12-month jail sentence plus a £20,000 fine, warns the Department for Transport.
Vehicles already fitted with the devices will not be affected, but anyone who now wants to equip their motor will have to buy a pedestrian-friendly alternative.
The safer bars, which are made from energy-absorbing plastic, have already been tested by manufacturer Concept Mouldings. Its Endura Frontal Protection System (FPS) is available for a range of 4x4s, including the Mitsubishi Shogun and SUVs from Land Rover, Ford, Nissan and Toyota. Pedestrian safety concerns prompted the new EU rules.
Transport Research Laboratory statistics reveal more than 900 UK and 12,000 European pedestrians and cyclists are killed every year, but the new bars could help reduce these figures. A Concept Mouldings spokesman said: "Our bars absorb lots of energy, and help to protect pedestrians from hard parts of vehicles."