Asklemmy

I am not a lawyer of any kind. The wiki does say:

"Many civil law systems, which are common in Continental Europe, Latin America and much of Africa, impose a far more extensive duty to rescue.[3] The duty is usually limited to doing what is "reasonable". In particular, a helper does not have to substantially endanger themselves.[23]

This can mean that anyone who finds someone in need of medical help must take all reasonable steps to seek medical care and render best-effort first aid. Commonly, the situation arises on an event of a traffic accident: other drivers and passers-by must take an action to help the injured without regard to possible personal reasons not to help (e.g. having no time, being in a hurry) or ascertain that help has been requested from officials."

To apply this to your question, my interpretation is that if you come across a car accident and nobody is there, and you have some first aid training, you should first call emergency services, and then render as much aid as you reasonably can without endangering yourself. If the car is teetering on a cliff about to fall over, I sure as heck wouldn't jump in. If the driver was ejected from the car and they are bleeding to death right in front of you then you should probably do your best to stop the bleeding if you can I guess. If the driver looks like they sustained heavy injuries and the car isn't about to explode or fall of a cliff, then I would just hang out until an ambulance gets there because I wouldn't want to break their neck moving them. Idk though, not a lawyer or a doctor so who knows.