I was a bit afraid of cycling in Spain after what I heard : “there are no cycling paths and Spanish drive like crazy”. Well that's not true. The cities do have cycling paths and Spanish are very cautious on passing cyclists. Another pleasant surprise: there are many good roads that hardly have any traffic because there is a motorway going in the same direction. With so little traffic it is like cycling on the widest and best cycling path ever.
There are also some roads to avoid in Spain. One of them is is the N120 from Logrono to Burgos. In this case the motorway A12 goes over into the N120 at San Domingo de la Calzada.
While I was trying to find alternative roads taking long detours, Komoot (my navigation app) kept on directing me to this very dangerous part of the N120. Komoots algorithm clearly is optimises for the shortest route and does not care much about safety. So my advice is to inspect your map for such situations and try to avoid them. Where N.. road is close to an A.. road in the same direction you will be fine on a very low traffic road. When the A.. road goes over into an N.. you may find yourself in situations like this: