I think the real problem with speed limits has nothing to do with where they are set. If the limit is 55 and drivers are mostly going 75, then there is a 20 mph difference between the speed of the speeders and the speed of those who observe the limit. If the limit is 70, and the traffic generally flows at 80, you might be safer than you would be in the 55 - 75 situation. In heavy traffic, the ideal situation is to have everybody traveling at about the same speed.

This weekend, I am going to go through Atlanta where the speed limit is actually posted at 55. (snicker) I will be pulling a red trailer, which I hope will protect me from rear-end collisions, because I will be going about 65. Many trips through Atlanta have convinced me that 65 is about as slow as you can go with any degree of safety. Certainly, if you try to change lanes when the gaps in the traffic are very small, and you are trying to get into a line that is moving faster than you, then you will have problems. That red trailer will give me some protection because it is highly visible, but it also gives other drivers a hint that I may not have the performance of a vehicle without a trailer. So, they give me more room and a little consideration. When I change lanes, I have two turn signals blinking instead of one, and they are never sure of how well I can see them.

In this day and age of electronic gadgets, it is possible to strictly enforce speed limits, but they should be set reasonably. And they should be enforced or eliminated. If speed limits are a mockery, who is going to respect other traffic laws?
Howard