I own a Prius C 2013. I read about Pulse and Glide, and I also watched youtube about it. I somehow have never seen a situation where there is no arrow in the Energy Monitor. The best I have ever seen is arrow coming out of the battery only which is EV mode. Some people say 35-45 is the best speed for P&G, but I never see "no arrow". What speed makes the car run without arrow?
I used this video when I was first learning about P&G. Although he's referring to a liftback, virtually all of the techniques he teaches in this video can be used in the c as well. Max MPG Driving Techniques Youtube Video | PriusChat