Do we need speed limits on highways?

Sometimes I drive on highways in the northeast and despite being empty roads; the speed limit does not make sense to me. As you go further away from the Northeast, you will find speed limits increasing. Maybe it is because of the sparse population or maybe something else but do we really need the speed limits when there are very few cars on the road and you are adhering to the same old speed limit. I know that it has been scientifically set that there should a speed limit but it cannot be proven with fact since in Germany, the autobahns has no general speed limit. Granted it has also accidents but if we can have a recommended speed limit rather than by law, people will generally adhere to it. I believe that during rush hours and congested and local roads, there should be speed limits but if there are expressways and highways and freeways, there should only recommended speed limits. But you know that even if you post some kind of speed limits on highways, there will always be people who will drive sometimes below the posted speed limit. So to post a speed limit on highways does not make sense to me since the people who will drive faster than the speed limit will do that anyway and the people who will drive below or near it will do it anyway with or without the speed limit. It is time to scrap this statutory speed limit on highways and post with a recommended one, although I know that the states will lose revenues due to no speed limit fines but they can still make it up in some other way and as for loss of lives, they will have to do more scientific study to find out if the posted speed limits in other countries have lower death rates than ours or not.