In ancient times the Appian Way, which links Rome to the southern city of Brindisi, was known as the regina viarum, the queen of the roads. But these days its crown appears to be tarnished by chronic traffic congestion, vandalism and, some of its guardians grumble, illegal development.

The abundance of monuments on the Appian Way, like the tomb of Cecilia Metella, above, has not deterred unregulated growth.

“Look at this!” bristled Rita Paris, the Italian state archaeological official responsible for the Appian Way, peering through a weathered bamboo screen lining the road while bumpily maneuvering her car through a patch of uneven ancient stones. “You can bet that it was once a canopy that was walled in and transformed into a home.”

A bit farther on she fumed about a plant nursery that had become a restaurant (without planning permission), a cistern that had morphed into a swimming pool, and the new villas tacked on to ancient monuments. Several are rented out for wedding receptions or society balls, which makes for a steady stream of traffic — and occasionally, “fireworks,” Ms. Paris said with a shudder.

Considered prime real estate in ancient times, when the Romans buried their dead along tomb-lined roads outside the city walls, the Appian Way underwent a contemporary renaissance in the 1960s when Rome was known as the Hollywood on the Tiber. Italian film stars moved in en masse, although today it is mostly home to the moneyed.

But these days some residents seem indifferent to the roadway’s archaeologically rich past, said Livia Giammichele, an archaeologist who, like Ms. Paris, has been waging a campaign against denizens whom she describes as “neo-barbarians.” They “don’t always realize that they’re living in special conditions,” she said.

What especially galls the archaeologists who monitor the thoroughfare, which was begun in 312 B.C. by the censor Appius Claudius Caecus, is that several laws govern the Appian Way, at least on paper.

Although the idea of creating a public park along the roadway dates from Napoleonic times, it was only in 1965 that a 6,000-acre lot was designated for that purpose. In 1988 the Lazio region instituted the Regional Park of the Appia Antica, a crocodile-shaped green expanse in southeastern Rome.

Technically this means that the area is protected by strict laws to conserve this natural habitat. The abundance of ancient monuments, both seen (like the tomb of Cecilia Metella or the catacombs) and unseen (because they’re on private property), should also preclude unregulated development under Italian law.

The reality is more complex. The park area is vast and difficult to monitor. (In tracts leading out of the city “there are acts of vandalism almost every night,” Ms. Paris said.) And over 90 percent of the park is still private property.

Complicating the situation, three amnesties on illegal building have been approved by national governments since the early 1980s. Critics complain that condoning past abuses only encourages more illegal construction.

“You can’t build a Berlin Wall around it — that’s not the most modern solution,” said Adriano La Regina, the president of the regional park, who was formerly Rome’s top archaeologist.

Even if it could be roped off, that would not resolve the question of who’s in charge. “There are a mass of administrations and institutions involved at municipal, regional and administrative levels that can make life very complicated because they each touch on some aspect of running the park,” Mr. La Regina said. A unified purpose has yet to take shape.

If archaeologists ruled the ancient road, he declared, it would reclaim its royal status as “an extraordinary historical monument.”

Over the last few years archaeological officials have successfully lobbied the Italian Culture Ministry to have the state acquire some of the properties that have come up for sale on the Appian Way. In 2002 the state bought a large villa in an area known as the Farmhouse of Capo di Bove. Excavations in the gardens revealed the foundations of a 54-room thermal bath complex.

The villa itself was built in the 1950s, and the outside walls are coated with recovered archaeological artifacts like amphora lids, marble inscriptions and terra cotta tiles. “They shouldn’t have been able to do it but they did it,” Ms. Paris said with a shrug. It will soon house the archives of Antonio Cederna, a journalist and political activist who campaigned to preserve Italy’s heritage and was a vociferous advocate of the Appia Antica park.

More recently, the Culture Ministry acquired and is now restoring the church of Santa Maria Nova, which abuts the spectacular second-century A.D. Villa of the Quintili, about five miles from Rome’s city center. Near the church they found mosaics depicting gladiators. But work on the site stopped earlier this year when money ran out. The ministry’s budget for the Appia is about $1.5 million a year, which never goes far enough, Ms. Giammichele said.

Life on the Appian Way isn’t always easy for residents either. Paolo Magnanimi, who manages the restaurant Hostaria Antica Roma, which he says opened on the Appia in 1796, suggests that while cultural officials are right to seek protection for the neighborhood, they should be more accommodating. “They can’t always be looking at things with the eyes of a gendarme,” he said.

When his father bought the restaurant in 1982, Mr. Magnanimi argued, he gave new life to something that had been abandoned. “Controls are fine, but keep in mind that we took a monument that could have ended up in a private home and opened it to the public,” he said. “Anyone can come in and look at it — you don’t have to eat a plate of pasta.”