We have those here too, they are used as solo or dual obstacle too keep speed Down.
The rules are the same as if somthing was parked in 1 side of the road, the side where the obstacle is have to stop for oncomming traffic. ( if there is 2 obstacles Danes go into panic and do whatever they feel like )
They are allso used in some cases to safeguard the damm bicyclists ( i curse them bcuz 95 % of them done give a f..k about the law or rules )
Allso those bollards are used here random aparently.
Have a look at the latter half of this video, its a intersection where every one have to stop for ppl comming from the right and make sure ppl from the left are stopping for you ( as you are on ther right side )
These intersections are a nightmare, and making them even smaller with 8 bollards dont make it better as most Danes have no clue as to how wide ther car is, and if you have a accident in sutch a intersection the Insurance Companies go 50/50 no matter how it happened.
http://www.youtube.com/watch?feature=player_detailpage&v=Jc-f9F-y0F0
We allso have bumps in the road to slow Things Down, they can be either right across all lanes in the road or only half of 1 lane, allso we have "turtleshell" bumps witch is round bumps on the raod approx 1.2 M i diameter Places asymetrical in lanes.
All those bumps cost a lot of bus drivers ther job as ther back got ruined by all the bumps they had to cross every day, hence they have begun to remove some of them Again.
Allso many of those bumps where / is outright wrong made, so even if you are within speed limit the bump give a too high G-load to the car.