I go 22 Km each way. Have to start work early and so I'm pedalling by 6am. In the morning with not much traffic, average about 23 km/h on a standard Trek touring bike. Slower if I use my mountain bike which I do if I'm going to the pool after work (I think its less attractive to thieves). Lucky to average 20 km/h on the return - lots of hills and intersections.