I carry 1 rear pannier on my bike. My commute is 14 miles each way. I usually go 13-15 mph on the way to work to not get too sweaty. I usually just use a wet hand towel to wipe myself down when I get there and bring a change of clothes. On my way home, maybe a little faster like 16mph since I do not have to worry about sweating. Stopping at stoplights and stop signs is the biggest factor in slower average speed (even with my tracker auto-pausing).