Any one tell me the logic for cyclist riding two abreast, very common down our road which is a narrow lane and part of a national cycle route.
If there is a group of cyclists, side by side, they present a shorter obstruction so in some circumstances, a group side by side can be easier to overtake.
If the road is narrow, there is also the factor that even 'singled out' (language in use among club cyclists) a pass is risky for the cyclists. So it is possible the leader of the group will not call for singling out until it's safe to overtake.
There is a load of other factors, but that is two of them.
