<map lat='45.54212640510885' lng='13.718769550323486' zoom='16' view='3' float='right' />
Probably best to walk towards this spot. You know you're there if you are standing on a bus stop and you can see a yellow sign that says 'Ljubljana-left', 'Olmo-straight', 'some street-right'. If you want to get to Trieste it's better to have a sign because most of the cars are going towards Ljubljana. You can also ask for a ride to the first or second petrol station on the highway and ask drivers who stop there to give you a lift (it worked for us once, when it was really late). This spot is well lit so it's doable to hitch hike from there after dark.
We never used this spot because you cannot see it from the round-about in Koper (check map). We took a bus and were passing by it. It is a bus stop, I can imagine it to be quite alright, the cars were not going too fast. You need to test for yourself if hitch hiking there works. When going to Piran accept lifts to Portoroz - Piran is 2 km away, it's a nice walk.