Having done my share of crashing at speeds from 5 mph to 50 mph, here's a couple of non theoretical real world observations.
1. Hit something square on, it really hurts. It hurts the bike, and if you yourself hit stuff square on it hurts you. No avoiding it. Brakes help a LOT, since the slower you hit something square on, the better. However, even 5 mph impact dead on can still hug you up but good!
SO DON'T DO THAT!
2. Hit something much more obliquely, and you slide off it, or if the earth itself, you slide down it. Much much much much prefered to the dead stop, as in the leap out a window example.
So how the hell do you turn #1 into #2?
Master the laydown. Don't hit that car head on, slide into it feet first, and do it with no hesitation when you must.
Master the skidded rear tire. While laying on plenty of front brake, but not locking it, lock up the rear tire and steer with your ass, and counter steer with the front tire. That is, point the front tire where you want to go, no matter what kooky angle the whole bike may be at. Adjusting where you lay it down by just 2 feet can save your ass. Ideally, you park yourself between the rows of cars, or to the left of that hugger that just left crossed you. Typical manuver, you just got left crossed. You can brake and hope you hit him slow, but you won't because he's moving towards you doubling the impact speed. Or lay a sliding skidded turn to the left, just missing him, and the rows of cars going straight ahead. Thread the needle between onrushing cars going straight and the car that just left crossed you.
Riding in dirt is the best place to master the skid turn, then take it to asphalt and practice it there.
30 mph, is in my opinion, a pretty safe speed for any decent bike. Brakes and frame flex tolerable. Above that, you really need quality, or motorcycle. But if you don't know how to skid a turn or do a laydown ,you are in danger at 30 mph. You are just going to have to take it like a dog when a car pops into your path at 30 mph. It's not if, it's when. If you don't have bike handling skills, you might want to slow down, and get the hell off roads with 30 mph speed limits.
I totally agree that not getting passed so much is a good thing. Just be aware, that when following a car at speed oncoming cars don't see you. You WILL get left crossed more, just like you do when riding a regular motorcycle. So you must be ready for that hazard, now that you eliminated another. What you do by speeding up, is simply trade what whacks a bicycle for what whacks a motorcycle. And don't forget to add your speed to the speed of the car that whacks you, for that kind of accident.