Well that would be the case if you assumed that cycle trips were evenly spread throughut the day, that a cycle trip typically lasted for 1 minute and that it was just as likely to occur on any part of the super highway. In the real world, typically each rush hour will acount for about 20% of the daily volume. Now, not all those journies will traverse the whole route so if we assume a 4.5m mile journey then about half of those cyclists would be expected to pass any given point on the cycleway (more on busier stretches). So 9000 trips/day would mean over 30 cyclists per minute passing busy points of the route. They may have justified the cost based on that volume of traffic, but they certainly haven't designed the route to be able to remotely accomodate it.