If one sees an accident in Germany they are required by law to assist. If one cannot stop or is unable to help then they need to at least call for emergency services. This is especially expected of car drivers who see an accident. In America, the legal situation is that one fears to actually help because they are likely to get sued. The reasons are often that they were not qualified to give any medical help or move the person.
In Germany you can be punished for NOT helping because they take a different view. All cars must carry an approved first-aid kit. They realize that first-aid is not to be a complete treatment but rather to just keep the people alive, or limit damage, until the ambulance arrives. Thus any help in serious cases is better than none. Also, it is a requirement to take an extensive first-air course to get your driver’s license. Not required but recommendable is to repeat such a course every few years. They cost some time and money but you’ll feel better for doing it if you ever need to use those skills.
Sometimes different organization or clubs might sponsor such a course on the weekend. Often intended for their members, it cuts the cost to attract additional participants if they don’t have enough. Such a situation might cost the half of what one would normally pay. Unfortunately, such an offer is rarely advertise other than word of mouth. But when you hear an acquaintance mention that his volleyball team or chess club is doing a course, think to ask if you can’t get in on it too. Even if you don’t drive, it’s worth it. Things like CPR are not difficult but uneducated people are either going to get it wrong or be traumatized by doubt.
Despite the law, many people often drive right past an accident without stopping. If you don’t see others obviously helping, it’s your duty. There is a legal and ethical exception; if one fears for their own safety. If a woman is on a dark, deserted road in the middle of nowhere - and a car to the side of the road is pulled over rather than wrapped around a tree, one might fear that it is asset-up for robbery or worse. In this case, one should at least slow down to assess the situation. If one doesn’t stop at the scene, they should continue until the first possible chance to call for an emergency vehicle. If uncertain, let the police or emergency services handle it.
All vehicles are also required to have a reflective emergency triangle to warn on-coming traffic and an orange or yellow emergency vest for your person. The actual usage of the vest is NOT required in Germany as it is in many other European countries – but you need to have one along. One should put the vest on and set the triangle up a good distance before the accident. The distance is not set by law but should be judged according to the traffic situation. 40 meters might be enough on a slow moving residential street with a 30 KM/hour speed limit. On an Autobahn or fast moving road, 100 meters or more might be better. One’s instinct says to rush to the victims first and leave the other rules for later. The risk is that the next vehicles that come along smash into the accident scene, or you, or your car. Taking these precautions to avoid escalating the problem are sensible - and the law. Sometimes this gets ignored and what turns out to be a minor accident becomes a major one or fatality.