Thanks. Yes, drivers are confused to see a bike going that fast.
I find to be safe, if I am riding with traffic, I ride it like a motorcycle... if I ride too close to the curb, drivers behind me want to get up beside me, whether to take a look, or whether to treat me like a bicycle ... either way, if that happens, I always ease off and let them pass.
In general, I try not to ride with traffic. If I see cars coming up from behind, I let them pass, then trail them so that I have no cars behind me. I prefer not to be leading traffic, as some drivers do not have patience and want to pass me, even if I am going the road speed limit.
In terms of upgrading the controller, I would refer you to Justin at ebikes.ca. He seems to have the proper knowledge to advise. If I were you, I would consider buying a proper controller to meet your needs. Kelly controllers appear to be the way to go for higher AMPs.
Rory