I carry a small first-aid kit I put together myself. Band-aids, a SAM splint, several 4x4s and a few pairs of gloves, the kit is in a plastic bin the size of a small shoebox. This kit has been used many times... by me on my family. I consider it my family first aid kit. Nothing in it is anything fancy, everything was purchased at CVS with the exception of the SAM splint that I bought on Amazon for like $4. As others have stated, the best thing I can do if I witness an accident is use my phone to call 911. It's the best "assistance" I have to offer.
I'll help out to the best of my abilities and available tools, but I live in an urban area where ambulance response is roughly 10 minutes. I don't live in Vermont, but if I did I'd usually be invoking this clause in the statute to say, "Nope, I can't stop": "...can be rendered without danger or peril to himself or without interference with important duties owed to others,..." I usually have one or both of my kids in the car with me, and I will NOT leave them alone in a car to get out and play Johnny & Roy at an accident scene. If I did, I would expect DCFS to be called on me, and I'd probably have my kids taken away.