I've compiled figures for the number of four-way full access freeflow interchanges in every EU country. Here is a summary of results:
http://i.imgur.com/bZOSSZQ.png
'Stack' includes classic four-level stacks and stack-turbines like this.
'Turbine' includes turbines like M3/M25 as well as windmill/octopus-type designs.
'1 loop' refers to single loop designs like A19/A66.
'Cloverstack' includes classic cloverstacks as well as partially-unrolled cloverleafs and other designs with two loops in opposite corners.
'2 loop' refers to designs with two adjacent loops like this.
'3 loop' refers to triple loop designs like this.
'Cloverleaf' includes classic cloverleafs and other four loop designs like this.
'Other nearside' refers to any design lacking offside entries or exits that does not fall into any of the above categories.
'Offside' refers to any design with one or more offside entries and/or exits, which I define broadly to include junctions where one of the mainlines merges or diverges (e.g. this).
A few comments:
- Of 672 qualifying interchanges, 384 (57%) are cloverleafs. The next most common grouping is 'offside' (13%), followed by three loop (10%), two loop (7%) and cloverstack (6%). There are fewer stacks in the whole of Europe than there are in some individual American cities.
- Unsurprisingly Germany 'wins' with 245 qualifying interchanges, followed by Spain (101), Italy (62) and, impressively for its size, Portugal (42). The German state of North Rhine-Westphalia has 68, which would rank it third in the EU were it a country.
- The UK has a pathetic 13. France also has relatively few (29) for its size, while Cyprus, Malta and Slovenia have none.
- In terms of national distribution of types, the UK has most stacks (3), Belgium and Italy tie for most turbine (5 each), and Italy also has most 1 loop (4). Germany has most three loop (23), offside (23), and, of course, cloverleafs (181). Spain has most cloverstacks (8) and 2 loop (11).
- The most notable 'disqualified' interchange is E75/E94 in Athens, which has tolling booths on its slips. Other grounds for disqualification include pedestrian crossings, level crossings, traffic lights, at-grade long turns (e.g. left in a right hand traffic country), and four-way merges or diverges.
EU interchanges
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