Roads to Rome

Vatican can't really "experience huge spatial growth" from this experiment. It is surrounded by Rome. Traffic from any origin point will reach Rome before it reaches The Holy See. I understand that this has probably happened because the calculation is to a specific "centre of the city" point, which means that any traffic entering Rome from the Westish will hit Vatican first.

Looking at the interactive map is fun.

For some reason, it's faster to get to Paris from Hemel Hempstead that it is to get to London. And the opposite is true of Pont-l'Évêque. I originally wondered if this was calculated using active traffic data, and a couple of particularly bad traffic jams might have skewed the results.

But then I looked for others: Montreuil to Brussels is very odd, as is the strange case of travellers from the Faroe Islands driving through Denmark, Germany and the Netherlands, before reaching their nearest capital in Brussels.

The oddest example of this is that travellers from half of Apulia find it quicker to drive straight past San Marino, Ljubljana and Zagreb, before reaching Sarajevo.