Remember about the thing with averaging is, is that it is much harder to increase the average speed of a ride than to decrease. If you slow down at all during a ride (whether it be hills, coming to a stop, wind, etc), the average speed will be affected easily. For example, I rode a 5 mile loop in a neighborhood with 5 stop signs. Even though, in between the stop signs I was riding at 25mph (most of the ride does not have stops), at the end of the ride, completing 20 miles, my average was 19.5. I have to factor the stop signs and how slowly I approached them, which due to the all vehicular traffic, the stops were slow. It also was very windy and rainy, always fun. Hopefully this might also explain the "slow" average, which by the way, 16-17mph average is pretty darn quick.