Parking depends on the situation. For example, I used to be an EMT. If we were first on, we'd park upstream, to act as a traffic barrier. The trick was parking so that we could get out once we had our patient. If we weren't first on, we'd park downstream so we could leave without passing the scene.

Limitations! Know them.

Don't get tunnel vision; make sure you tell 911 an accurate description.

DO NOT BECOME A VICTIM! If it's in the middle of I-95 at 7pm on rain-slicked roads, you're just setting yourself up to be killed by traffic.

If you want to help, be ready to leave when told. Some folks are great to help, others are complete a$$holes that endanger folks. Get in the way, you may be arrested. Most EMS/Fire folks have no qualms getting PD involved.

If you don't know how to triage, learn. It's all well and good to try and do CPR on someone, but if you've got 3 folks in the next car and they bleed out and die, you've killed 3 (and still probably not saved the first). You NEED to manage time and resources when you're the only one there.

Honestly, as EMS, random folks being first on are kind of scary. Too much "wannabe" attitude (even saw a guy with a Crown Vic and amber light bar, trying to be like a cop, even with dark blue clothes). A police dept. I used to work with actually confiscated a guy's FAK, vest, and helmet. Why? It had the Star of Life on it, which is a trademark. He wasn't an EMT, medic, or associated with EMS in anyway. We ended up taking half his stuff and throwing it on our ambulance - his equipment was top-notch, but he was a hazard to others.

Lastly, again, don't become a victim. Gloves at the least, eye protection and a mask if there's squirting fluids. Traffic hazards, environmental hazards (are you going to freeze on the side of I-95 in january once you give your coat to someone in shock?), legal ramifications (though Good Sam. laws usually are pretty good), etc. Don't feel like you NEED to help. Only do it if it can be done safely and help others.