DDOT has a presentation on their website about the 15th Street bike lanes. Looking at DDOTs results from the pilot program study, I think it's safe to call it a success. The change has resulted in slower speeds and less speeding, while moving slightly more vehicles (but fewer by car). Cycling is up 40% on the street and there is 12% less sidewalk cycling. Most users feel it has made the road safer. It's had a positive return on investment due to trips switching from car to bike, more activity and reduced injuries. (It does not appear that the cycletrack is moving as many vehicles as a full lane, that may have been a misunderstanding on my part).
The next step is to extend the cycletrack and change it to a two-way cycletrack. The design is also online (though I haven't had a cahnce to look at it yet). This will be implemented over four weeks during September and October.