It's only my opinion and my experiences are merely personal anecdotes but hitching anywhere in CONUS is bad and far less safe for hikers than those that pick them up.
I have a fairly clean cut appearance (no tats, newish shoes, casual attire, usually clean shaven et.c.) And I've mostly only hitched around or near Appalachian trail Towns.
That's the best hitching. I hitched in south Texas and got more rides from the border patrol than others. they were just checking me out tho and getting me out of the area they patrolled.
Almost every hitch I've ever gotten I wasn't even trying, someone just stopped and offered and a few times I said, nah.
I'm a pedestrian and never in a hurry. I know bad juju is chiming when I feel like I need to be somewhere other than where I can get with my feet.
This old Bastard has drug his ass over 15k miles in less than 8 years on just one step then another then another...
I'd never recommend a woman to stick a thumb out. It's a less safer option than your feet and what's the hurry anyway. Free and easy traveling, hitching, train hopping, squatting, community is along the Towns of the Appalachian trail.