ROME—In a bid to protect its ancient glories from modern perils, Rome is banning cars and motor scooters from the boulevard that slices through the city's ancient forums toward the Colosseum.

Traffic police started enforcing the new restrictions at dawn Saturday, diverting private cars and motor scooters to side streets, so they will no longer clog the Via dei Fori Imperiali.

Only buses, taxis, bicycles and pedestrians will be allowed on that boulevard, which was constructed in the 1930s by dictator Benito Mussolini so military parades could roll past reminders of the ancient Roman empire.

Mayor Ignazio Marino announced the ban shortly after his election in May. He says the ban will stop the Colosseum from being a traffic “roundabout” and reduce pollution.

Sidewalks have been widened so people can stroll in leisure down the boulevard.