Lucky Number 7 - If you ride around the east side (Woodinville, Bothell, Kirkland area) you see these markings on the road side. The number 7 stenciled on the roadside is the route for the Seven Hills of Kirkland When an organized ride is held the organizers go out and mark the route with Dan Henry Markings. According to Wikipedia:
Dan Henry (b. 1913) is a bicycling legend and inventor of directional pavement markings commonly used to guide participants along the route of organized bicycling events. The markers themselves are usually called "Dan Henrys".
An example "Dan Henrys" for six different routes.
All indicate the same direction of travel.
Originally, the markings consisted of a circle with a vertical line from the edge of the circle pointing in the direction of travel (up, left, right). Other common markings are a circle X to denote wrong way, and a circled horizontal line to denote caution.
Variations on the circle pattern developed to differentiate between different rides as more and more rides began to use the same roads. Variations include color, triangles, squares, letters, etc.
I picked up the route off the Burke Gilman Trail where I spotted the first #7 on the pavement - I made a quick left and immediately went up a hill. I continued to follow the #7 markings as they wound though some pleasant neighborhoods. The route was a nice change from my usual rides and had some quality hills. Somewhere along the line I missed a turn and ended up on a very busy road where I would not have chosen to ride so I knew I wasn't where I should be. I ended up in Kirkland and took a break for something to eat. Because I had other plans for the evening I wasn't able to complete the ride and ended up hopping a bus across 520 to get home at a decent hour. It's really nice that the buses that go across the lake have room for 3 bicycles but I don't understand how they can charge you full fare when you are only on the bus for 2 or 3 miles.
I looked at the website this morning and found where I had gone wrong and printed out the cue sheets. Turns out there are several routes besides the traditional 7 Hills - there is a metric century and a full century option. For folks looking for a good ride in the Seattle area - here is the link.
Seven Hills of Kirkland