I had read a newspaper column about road accidents and 1 point was the bikers who are riding in tandem. The statement was probably referring to bikers on the main road. I agree that it is risky to ride in tandem because of the vehicles which are usually speeding when there is no traffic. As cited by the columnist, there were many cases where a biker with a rider at the back figured in an accident because of the difficulty in pushing the pedals. For me, I don't think I would ride in tandem on a bike in the main road.