A motorized bicycle limited to traveling 20mph on busy roads is a hazard for rider and motorists.
Of course, going 45 in a 25 will get you in trouble, not matter what you ride.
I'm an old guy too.
I try to ride defensively and smart, keeping a safe distance from cars.
I like to get the jump on traffic at the lights.
When they're stopped, I merge from the side street and create a large distance.
Orrr, I'll let all the cars pass me, then make my way.
There are certain isolated bike paths and sidewalks on my way home that allow me to ride safely.
And of course, pedestrians and bicycles have my great respect.
If you don't act like a discourteous maniac, the local police will let you ride.