This is why Ree carries a length of battle chain - most four wheelers will not stick around after hitting you if they see you get back up.
At the very least, you can cost them a windshield and make them easy to identify as they spin tire away from the scene, at best they will stop and make an issue of it, and still be doing so when the cops arrive.
(not to mention the personal satisfaction possible in that situation...)
One thing to really watch out for is the shove-over or bumpNrun attack.
This is when a four wheeler either -
A - decides to deliberately sideswipe you and take off.
B - keeps forcing you over till you hit a fence, wall or curb.
In either case, as soon as you see it coming, jam the brakes and get a plate number before turning off to hide, use your vehicles lower ground pressure and smaller size to best advantage in doing so.
Also nasty is the rear-end push, when some damnedable fourwheeler decides you should run the yellow light cause he's in a hurry, and pogos yer cargo rack, usually causing you to dump the 'ped on it's side...such folks almost invariably exit the vehicle with hostilities in mind as soon as you get back up, and the safest course is to drag your 'ped out of thier path before they run it over.
(My preference is to take out thier headlights and then do that, but not reccommended for legal and safety reasons...)
All in all, your best bet when nailed by a car on a 'ped is to stay down, till the cops get there, most folks run as soon as you get up, as long as you stay down they usually won't bolt, due to the legal difference between 'leaving the scene' and 'vehicular homicide', etc.
I would reccommend using common sense and a good knowledge of the law, and preparation beforehand, so you know how to handle it in advance.
(and wear a helmet, law or no law.)
Supposedly the law protects you, but I've had enough cops laugh in my face to prefer dealing with it personally and immediately, and most insurance companies will refuse even mandatory legal obligations (such as PIP coverage) to you, and there isn't really much you can do about it save complain to your states insurance commissioner (who will also laugh you off), and hope for the best.
FYI - PIP doesn't cover motorcycles, but it considers bicyclists pedestrians, and according to your manual, your vehicle is a "Motorized Bicycle" making you legally entitled to PIP coverage, usually about $2500.00 no-fault, in many states.
But again,...just try collecting it - good luck.
My preferred methods aren't niceNfluffy legal, but they work - you are however, on your own if you should attempt to use them - you have been warned.