That's my bike, but if he's riding on a road like that, he might be better off on a cross bike if it's somewhat rough. I mean the fat tires on the Muirwoods 29er soaks up a lot of stuff, but for long distance, the position really isn't ideal as far as a aerodynamics go. In an urban environment where speed is dictated by stop lights and traffic, it's not such a big deal, but on open road like in that photo, the situation is quite different. I mean it's very seldom that I go more than about 500 ft without stopping or slowing down.

Look at the plot of my speed indicated by the purple graph. I think the resolution is one reading per 10 seconds which is why it does not indicate a zero reading at every stop; but then again a lot of stop signs I coast through at a low speed if there is no traffic.