Legally speaking, you only have an obligation to follow the traffic laws while you drive. As long as you do so, you’re contributing to overall safety on the road. In theory, if everyone drove like that and did not make any mistakes, no one would get involved in car accidents.
Unfortunately, many drivers do not follow traffic laws. They do make mistakes. They do drive recklessly. Even if you do everything by the book, they can still cause an accident.
Defensive driving means taking things a step further and doing more than you are legally obligated to do. You pay full attention to the road around you at all times, you anticipate all manner of mistakes and errors coming from other drivers, and you react to them in advance.
For example, if someone is tailgating you and you’re driving the speed limit, any accident they cause is their fault. You can legally just keep driving. As a defensive driver, though, you can pull over to the side of the road and let them pass. You knew what they were doing was very dangerous, and, whether they understood that or not, you took the time to increase your own safety by going above and beyond.
Defensive driving can save your life. It is a great mindset to have. Every year, defensive drivers are able to avoid many car accidents. That said, no strategy is perfect when it comes to eliminating risk. You still face risks because there are still other people on the road with you. If you get injured in an accident with one of them, you may need to seek compensation.