Tunnels and Viaducts on the A50 Motorway in Italy, by Kilometre Point

• 2entries listed
• 0.34 kmlongest bore
• 0.43 kmtotal length

The record table

How this archive measures: lengths, bores, dates and ordering

How this table is compiled

28 rows are rendered in total, so 26 of them carry a note or a blank where a length belongs and are shown without being counted. Where one of these 2 lengths disagrees with an operator's own figure for Italy, the table keeps the published value and notes the difference instead of averaging the two.

A new scheme in Italy would have to beat 0.34 km to change the head of this table, and that is the figure worth rechecking when one opens. The note column records 13 exits, 7 motorway connections, 1 toll barriers and 3 service areas along the route, in running order rather than by size.

2 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Laid end to end the entries on this page would run 0.43 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.

The note column places the route in Lombardy, and the administrative area is recorded because a section is identified by it. A tunnel list for Italy reads differently from a neighbouring country's, because the same journey time can be bought with one long bore in one country and a dozen short ones in another.

The table on this page runs to 14 rows and records Viaduct, Direction S.Giuliano, Direction Arese and Notes for each of them, which is the shape the original compiler chose rather than one imposed here. The kilometre point is recorded for each structure on the A50, which is how the operator identifies it.

Reading the figures

11 of the 14 rows carry an entry in the notes column — 79 per cent of the table — and that column is where the qualifications live: tube counts, closures, boundaries and the reason a figure reads the way it does. Italian motorway inventories list tunnels and viaducts together in running order along the A50.

The entries sum to roughly 0.43 km of bore, an average of about 0.22 km each, though that average describes no actual row. The direction s.giuliano column sorts these 12 rows into 6 groups, the largest being - with 5, then Agip with 3 and Tamoil with 1.

The longest entry is Rho, at 0.34 km. The shortest recorded entry is 0.09 km against 0.34 km at the top, a spread of 3.59x across the same table. Italy's motorway network runs the length of a mountainous peninsula, which is why its structure count is so far ahead of its area.

The direction arese column sorts these 10 rows into 6 groups, the largest being - with 4, then Agip with 2 and 337 m with 1. A crossing whose two carriageways differ in length is recorded once per direction rather than once per crossing. Two administrations measuring the same crossing will agree on the rock and differ on the approaches.

Tunnel building in Italy is shaped by geology and settlement pattern as much as by transport policy. Wind, not weight, governs the design of a long-span bridge, and the deck section is shaped in a wind tunnel before anything is cast. The number of tubes is recorded because it changes both capacity and the safety regime that applies.