My 9.5 miles to work, taking the local MUP for most of it, has two stoplights, one stop sign and is mostly flat grade +/- 2. So with this almost perfect commute I average 19-20 mph in the summer, but I feel good about 16-17 mph in the winter. Average speed in my experience on my route is about 1 mph to at most 2 mph slower than the "cruising speed" you keep up between stops or hills.