I was experimenting tonight, pushing a slightly bigger gear than normal and trying to maintain the same cadence. I thought that I was just fooling around and I turned in my third best time overall for the route.
My average speed is still down in the 14's which isn't bad considering I ride through about a 3/4 mile long stretch of packed gravel in a construction zone - I slow down for that quite a bit. I'm hoping to get my average up into the 15's and beyond on a regular basis once that section is resurfaced.