This indicates that it is legal to make a right turn at this junction when the traffic light is red. This is a privilege that is only extended to cyclists. Drivers must always wait for a green light.
You can do this at many junctions where there is a fully segregated cycle path, and there is usually no sign then. However, at junctions like this where all the traffic comes together some indication is needed to show whether a right turn is safe at this location.
The video shows the way this works. You go from one cycle path around the corner onto another without stopping, and without having to worry about motorised traffic as none of it is in your lane.
Explanatory captions on this video are visible only if you play it on a computer and not on a mobile device
The keen eyed will have noticed that there is also a white and green sign underneath the traffic light. As well as allowing right turn on red, this is also a simultaneous green junction, go to that link for more information.
|From the CROW Design|
Manual for bicycle traffic
April 2006 / June 2007
There are several other blog posts illustrating the details of what makes Groningerstraat in Assen a good place for cycling.
Update 2015: Right on red is not new
Paris has achieved much press over the last few months for its implementation of right on red (and straight through on red) for cyclists. None of this is new. It's been normal across the Netherlands for over a decade now.