* New mayor pushes ahead with pedestrianisation plan
* Most of busy street Mussolini built over forum now closed
* Locals concerned about traffic worsening elsewhere
By Naomi O'Leary
ROME, Aug 3 A busy road that cuts through Rome's ancient forum to the Colosseum was blocked to private traffic on Saturday, in the first stage of a plan to pedestrianise the area that has angered some locals but which the mayor says is of global importance.
In the hours before the closure, motorbikes and cars circled the Colosseum beeping their horns and taking photos to mark the last time they would take a route immortalised by Audrey Hepburn and Gregory Peck's scooter ride in the 1953 film Roman Holiday.
The almost 2,000-year old arena, where gladiators fought bloody battles for the entertainment of vast crowds, has been blackened with exhaust from heavy traffic that for years passed close to its walls.
By closing most of the Fori Imperiali road that runs 1.1 km (0.7 miles) from the Colosseum to the giant marble Victor Emaneule monument, centre-left Mayor Ignazio Marino hopes to eventually turn the whole area into an archaeological park.
"We must chose whether we want cars or to value our monuments," said Marino, who has cut a distinctive style since his election two months ago by cycling to appointments, and has set about the pedestrianisation plan with remarkable speed.
"I don't think any other city in the world ... would have turned the Colosseum, probably the most famous monument on the planet, into a roundabout."
For now, taxis and public buses are still allowed to travel down the broad road that links Piazza Venezia to the Colosseum, in an experimental stage implemented in the quiet August days when locals flee the hot capital. Cars can still drive by the south-eastern part of the arena.
The building of the road straight over the remains of ancient Rome by the dictator Benito Mussolini remains a sore spot with archaeologists, but many Romans are fond of the striking avenue it created.
Groups opposing the plan said they would picket a concert to celebrate the closure on Saturday night.
"This will be at the expense of the few remaining long-standing shops and small businesses already plagued by economic crisis (and) taxes," far-right group Casapound said in a statement.
Some motorists fear the road closure will worsen traffic elsewhere in the capital as cars are diverted down smaller side-streets, particularly once the city fills up again in September. (Editing by Robin Pomeroy)