There are very many ways to die. There are also many reasons to be afraid of death as well because it is one of the few things that we can never know. There are many things that we say we will never be able to understand but there are only a handful of these that we know for a fact we can in no way research more or ever be able to understand Death is one of these few.
There are a lot of different ways to die in the world, as sated above. If you have a dream in which you see yourself dying in a car crash it means that you have to really think about driver safety. Something has probably happened to you recently which triggered this kind of thought or this dream .You do not normally dream of dying in such a specific way and you do not normally let a dream be triggered by something like this if you aren't worried in some way about what might happen in your life. Try to think of what it was that triggered this dream.
Maybe you ended up getting a speeding ticket recently. Or perhaps you just ended up rear ending someone on accident. You don't actually need to get in an accident to get the gears in your mind thinking about what could have unfortunately been. This is not a dream that comes out of nothing though and even if you are not in imminent danger you still need to realize that good driver safety is never a bad thing. Safety can always help more than it will hurt and you will do well to keep to this safety if you want to do well for yourself in the future.