If you are commuting , say , 40 miles, to work each way its too far to cycle realistically, for most. I suppose the idea of getting an hours exercise each way without effectively taking any additional time out of your day certainly would appeal to some.
I can just about squeeze 30 minutes exercise in my lunch break and struggle to fit anything additional in , leaving home at 6.15 and getting back at 7.30 so the idea certainly appeals, except I use the train , and the cost of the bus is rather high.
South of the River into London , pariculary the East of the city , is often quicker and cheaper by bus /coach. Its just a lot less flexible as the service outside the core rush hour tends to prevent any later working, particularly those who finish at 5.30.
Market the idea as " exercise while you commute", as opposed to the mirth inducing " cycle to work on a bus" strapline and does seem more sensible
