Sorry for the absence. I was busy running the bicycle parking at Bluesfest 2011, which is a 100-hour-a-week volunteer gig. You'll be happy to hear that I've got over two weeks of posts pre-scheduled, so there won't be another gap for at least as long!
Most of the time, when a pathway in the national capital region splits, the yellow line will follow the direction where the pathway continues in whatever direction. For example, if you're trying to navigate the pathways under the Portage Bridge to get westward from behind the Parliament buildings, following the yellow line will help you get back to the pathway along the Ottawa River.
Many cyclists don't realize this, but they do get it at an unconscious level. Take here for example:
This is just under the Laurier bridge heading North toward the convention centre and Byward Market, on the pathway that runs along Colonel By Drive. This is a notoriously difficult place to navigate because it's not clear at all how to get from here to the other side of Rideau/Sussex.
Unfortunately, when I stopped to watch for a bit, I saw most cyclists followed the yellow line up to the abutment of the Laurier Bridge, which led them to a dead end and a hard curb along Colonel By Drive. They, as I had done just before them, ended up going down the steep cobbled footings of the bridge to get back to the pathway along the Rideau Canal and continue toward Union Station.
Unfortunately, even if this line gets fixed (which it might, there was still some construction going on when I took this photo in May 2011), there's not much place for people to go once they pass the bridge, it's still every cyclist to him- or herself to navigate Colonel By, Sussex, and the rest.
[Look for more one-photo posts under the label Singles]