Hitching is never entirely safe, and we don’t recommend it. Travellers who hitch should understand that they are taking a small but potentially dangerous risk. People who do choose to hitch will be safer if they travel in pairs and let someone know where they are planning to go.
Hitching is illegal on autovias. Choose a spot where cars can safely stop before slipways or use minor roads. The going can be slow on the latter and traffic is often light.