It's been 6 years since I've ridden (legally) on the street, but over the years I've had ~30 motorcycles, and about 200k miles, with only 2 accidents that required an ambulance, which both occurred in the first 3 years. For many years, I didn't even own a car. Hauling a week's worth of groceries on an Enduro is an art.
Visibility and attitude are the top issues with survival. Cars do not see you, and you need to assume that when riding. Pretending they are actively out there with no other goal than to run you over is not a bad idea.
The model of bike isn't really important when you focus on visibility and attitude. But, bikes that "tempt" you to play ricky-racer aren't good starter IMO.
I like Enduros (dual purpose, dirt/street) for starters:
You sit high, and have excellent visibility, you can be seen better. A simple/ cheap exhaust mod can increase the sound level (not obscene, just loud enough to be "visible"). Wear a bright colored jacket and helmet. No, I'm not talking DayGloReflectorVest, I had a yellow Malcolm Smith jacket I often wore, and a white helmet. When the helmet/jacket wore out, I got new. I pretty much looked the same from 1970's to 2000.
Enduros are nimble, light, and fuel-stingy.