Great discussion all, and yes, those days when the lights are all green really help the average speed, I do have some long straights without any lights and a decent shoulder, but I also have to go though downtown Harrisburg where I have the choice of the multi use path, which if it's clear of peds and other bikes I can go fairly fast on, or hit the main road and just stand on the pedals for all I'm worth and hope to hit the 3 lights green till I circle around to the same road the MUP comes out to. It's a day to day, and I can't ever imagine getting over 20 without at least hitting half the lights green. But, I couldn't have imagined averaging over 20 last year hitting every light green, so progress is progress.
Also, every day isn't a race, some days I hit the pedals with the legs feeling springy and ready to see how hard I can go, others I just pedal, and end up home.
Joe