18 inch curb isn't so much a "concrete barrier" - it's a tall curb.

It is quite common for there to be a standard curb, but then include additional deterrence such as bollards, additional segmented curbs, or planters/plantings between general traffic lanes and the bikelane.

Another common thing to see is a mountable curb for parking, where parking is used as the separator. (There are good examples of this in Frankfurt, and horrible examples of this in Frankfurt.)

But it's not like the cattle chute Jersey Barrier separated bikelane that you can sometimes see (ineptly) installed around here.

The key point is it is not "just paint" separating the bike lane from general traffic.

-mr. bill