If you are just starting to drive in Spain and want a little reassurance on the regulations you might want to invest in a book by Brian J Deller called MOTORING IN SPAIN. If you just want a few pointers please read on..
Seatbelts Everyone must wear a seatbelt (where fitted). The driver is responsible for any fines for passengers who are not wearing one.
Children/Animals Children under 12 years of age must be seated in the back of the car with a correctly fitting belt or a “booster” seat to make the belt fit. Animals must be restrained when in the passenger section.
Drinking and Driving Don’t do it! The limits are very low (about half the UK limits) and the penalties very high including heavy fines, losing your licence and spending time in the cells.
Mobile telephones The use of a mobile telephone while driving is illegal except with a true hands-free system, ear pieces are not allowed. Even at the side of the road you may not use your phone you have to pull off the road completely.
Navigation aids and DVD´s etc. The driver must not use any screen based aid to navigation (or entertainment) while on the road. You must pull completely off away from traffic. (It makes sense really; after all, you are not allowed to drive down the road with a map on the steering wheel). DVD players and screen based devices other than those needed to operate the car must be positioned so the driver cannot see them.
What you must have with you
Driving licence, insurance (and proof of payment of insurance) and car ownership papers. Plus, if the vehicle is not registered in your name, carry a letter from the registered owner giving you permission to drive it (in Spanish).
A spare pair of prescription glasses if you wear them for driving.
2 EU approved red warning triangles
Approved reflective jackets. These must be kept inside the car so that you can put them on before exiting the vehicle.