I believe these flags mark the route of the new multi-use single track mountain bike trails.  

Lester is the eastern terminous of the  forthcoming 'Duluth Traverse' tail which will consist of 100 miles of trail from Lester to Mission Creek near Jay Cooke St Pk.  The route will be designed with more 'flow' in mind rather than much of the technical singletrack already present in Duluth.

The plan is to add another 5 mile multiuse singletrack loop in Lester as well as connecting it to the Duluth Traverse.

Biking year round on the trails. However, they are not exclusively for biking, like the ski trails are in the winter. Running, hiking and snowshoeing as well.  

I usually run on the trails. I am usually moving as fast as the bikes, except on the steep downhills. I have not had a problem. I usually step off to the side and let the bikes pass.

I ran on the Lester trail for over 2 years before seeing a bike on the trail at the same time as I was running.

The bikes don't go that fast, are able to stop quickly if need be and no one wants to run into a hiker.

In the next year or so there may well be a multi-use (incl. bike) loop built in the upper part of Chester.

Thanks for the information.  I look forward to another trail to explore!

I run and ride.  There's plenty of room for us all out there.  Keep up the great work, Adam.