My commute is 24km one way. About half of that is low traffic with few traffic lights, and on that section I am usually able to average 31-33km/h fairly easily. However, the rest of my commute has much heavier traffic, and so the overall result is that my 24km commute usually takes about 1 hour and 10 minutes to complete - but that also does include 10-15 minutes waiting for and riding the ferry across the river (bikes are not permitted on bridges or in tunnels in Shanghai).