Fig. 1: Motorway networks for different countries and regions.
From: How much longer do you have to drive than the crow has to fly?

Motorway networks (black lines) in China (a), France (b), Germany (c), Spain (d), the contiguous United States of America (e), California (f), Great Britain (g), Ontario (h) and North Rhine-Westphalia (i), respectively, with the locations (red dots) used to calculate distances. Motorway network data provided by OpenStreetMap (OSM) © OpenStreetMap contributors35,36. Maps developed with QGIS 3.437.