Some cities have what is called a “ring road” (raccordo anulare in Italian). You approach Rome, for example, from any direction, get on the ring road and then drive clockwise or counterclockwise entirely around the city to continue on your way, or you can use one of the many exits from the ring to drive into the city at the point most convenient for you.

The other kind of road to by-pass a city is called a tangenziale. Naples has one, the A-56. (No one I know really remembers that number. It’s just “the tangenziale”.) The idea for a road to avoid downtown Naples is not a new one. As early as 1850, the idea occurred to King Ferdinand II. At the time, if you wanted to go from the town of Pozzuoli, almost at the western end of the Gulf of Naples, into Naples, itself, you essentially followed the old Roman road, the Domiziana, through the towns of Bagnoli and Fuorigrotta, then through the still functioning ancient tunnel, the "Neapolitan crypt", that passed beneath the Posillipo hill to Mergellina. From there, you trotted along the Riviera di Chiaia, went along the sea through Santa Lucia and into and through the city.

The king had a new road—an early “tangenziale”—built and named for his wife. It was Corso Maria Teresa, today Corso Vittorio Emanuele II. It angled up from Mergellina away from the sea and to the east above and past the populated sections of Chiaia and the Spanish Quarter along what was then a sparsely populated area below the San Martino hill; then, it turned down a mile or so later to the National Museum, past the congested city. From there, it was easy to turn north onto via Santa Teresa degli Scalzi, itself a major elevated road built some 50 years earlier, leading over the densely populated section of Naples known as the Sanità and out of town past the Capodimonte palace. From the museum, you could also go straight to the east just outside the old city walls of the city along via Foria towards the other end of Naples. In either case, you circumvented most of the city. Other seaside roads from the early 20th century—via Caracciolo and via Marina—also provided another kind of tangenziale along the coast for the new motor-car traffic. From Mergellina you could drive straight along the coast, past the port and out of town. In the days before every family had two cars, that was actually not a bad through-road.

In the 1960s, the city decided to build an entirely new road, the tangenziale, from Pozzuoli to the airport. It would run in back of the city—that is, on the north side; the bulk of the modern city of Naples would then lie between the new road and the sea. A number of exits would take you down into the city; the corresponding on-ramps would also be a quick way out.

The first stretch of the new road was opened in 1972.Today, this 6-lane divided highway runs all the way from Pozzuoli to the Naples airport. Both ends hook up to other multi-lane roads; in the east, the tangenziale connects to the major north-south autostrada in Italy, the A-1, and in the west to the road that runs up the coast to Gaeta.

Road construction behind Naples meant going through and between hills; the 20-km (15-mile) stretch includes three long tunnels and a number of overpasses. It was all major engineering. Along the tangenziale, there are ample filling stations and rest stops, an SOS call-box every kilometer, and 14 on-and-off-ramps. Modern city traffic in Naples is unimaginable without the tangenziale. Sometimes, it is unimaginable with the tangenziale, but I have been stuck in traffic in the ring-road around Rome, too. (At those times, you just relax and beat on the horn like everyone else.)