TransLink’s 503 Surrey Central/Aldergrove bus route is a good example of what I might call a “half barbell” route: mainly straight and two way along most of its path but with a loop at the outer end to provide coverage through a neighbourhood, in this case Aldergrove. http://infomaps.translink.ca/Route_Diagrams/125/r503.pdf
503 South Surrey/Aldergrove as a half barbell route.