Originally Posted by Bruce Rosar

Well, I suppose that depends on exactly what it is. At least in my state, traffic isn't prohibited from sharing a marked lane if they want to. Wide (cars, trucks, etc.) can (sometimes) share with narrow (motorcycle, moped, equistrian, bicyclist, inline skater, pedestrian, etc.) and, of couse, narrow can share with narrow. Although motorcylists are limited to two side by side here, we once had four or five lanes of bicyclists within a marked lane during Cycle North Carolina.