Funnily enough, vehicles that approach from behind you do not present the biggest danger on the road. This is because vehicles overtake cyclists very carefully here in Spain
On the other hand, since cars are more likely to drift over lane markings to overtake other
cyclists, they also therefore present a special danger to you if you happen to be travelling in the opposite direction. Remember to always
keep your eyes open for oncoming vehicles!
Especially be on the lookout for local Titsa buses & tourist coaches who will swallow the whole road when they approach a tight bend. They're more likely to invade an oncoming lane if they're turning around a right hand bend (which are tighter than the same bend taken from the other direction).
If you're descending along these amazing winding roads & you approach a blind corner -then you suddenly hear a horn sounding from around behind it- move over to the right hand side of the lane quick
, because otherwise you'll splat yourself on a bus's windshield!
Watch out for storm water drains or grates, especially on the descents. There are a few located around mesa del mar (here in the North of Tenerife), and at least one I know of near at the entrance to the resort in Adeje, Las Americas, not far from Hotel Jacaranda.