Road Tunnels in Portugal — Complete List by Length, Part 000

• 69entries listed
• 0.47 kmlongest bore
• 2000–2006openings span
• 17.21 kmtotal length

The record table

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

How this table is compiled

The three longest entries alone account for 1.38 km of the 17.21 km on this page, which is 8 per cent of the total from 3 of 60 rows. 30 entries sit above the median and 30 at or below it, so the table is evenly weighted and not clustered at one end.

Between the longest and the tenth-longest the drop is 0.08 km, which is the part of the table that changes when a single scheme opens. Where one of these 60 lengths disagrees with an operator's own figure for Portugal, the table keeps the published value and notes the difference instead of averaging the two.

The longest stands 0 km clear of the next longest, which is the margin to watch when a new scheme is announced. Laid end to end the entries on this page would run 17.21 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.

Dated entries run from 2000 to 2006, and the busiest decade is the 2000s with 28 recorded openings. The table on this page runs to 70 rows and records Tunnel, Length (m), Year of opening, District and Notes for each of them, which is the shape the original compiler chose rather than one imposed here.

Second and third place go to Achada at 0.46 km and Cabeco da cancela at 0.46 km. Read down the length (m) column, the 69 values run from 27 m to 465 m with a midpoint at 280 m; the spread rather than the maximum is what says how uneven this set is.

Reading the figures

Lengths for Portugal are recorded in metres which is how the operators publish them and why the shortest entry here reads as 100 m and not a rounded figure. The 60 rows for Portugal are ordered by length, not by date, so the 2006 opening sits well down the table without being any less current.

Roughly 28 of the dated entries opened in this century, which is a rough measure of how much of the network is recent. The captions name 5 distinct places and structures — Brava-Airport, Caniçal and Machico among them — and those names are the index into the length tables where each is recorded with its own figure.

A new scheme in Portugal would have to beat 0.47 km to change the head of this table, and that is the figure worth rechecking when one opens. The longest entry is 4.7 times the shortest and 1.6 times the median, which is the quickest measure of how uneven the table is.

Dates for Portugal refer to opening to traffic, not breakthrough, so the 2000 entry was under construction for some years before that. Only 37 of the 70 rows carry anything in the year of opening column, so that field describes a minority of this table and the rest of the rows are recorded without it.

The dated entries carry 5 distinct opening years across 6 years, and the median opening year is 2004. The material on this page is held in 24 captions rather than in running text, 166 words of it, each written against the image or row it belongs to by the compiler who put the page together.