Where:
in a narrow crack
with the bike path on one side
firmly rooted rush

Juncus tenuis
Syltåg (eller stubbtåg) i december i februari, i juni och i mars
Eva Ekeblad, 2000/2005

The photo was taken later, on Nov 17th, by Jens with the ION.

There's both Slender Rush and Round-fruited Rush along the kerb on that stretch, the October sample looks more like Juncus tenuis, I think. Compare Juncus tenuis and Juncus compressus.