Correct me if I'm wrong, but the studies you're referring to are examining speed, but not speed limits. It doesn't seem to me that the two are equivalent. This

Correct me if I'm wrong, but the studies you're referring to are examining speed, but not speed limits. It doesn't seem to me that the two are equivalent. This might be another "tantalizingly counterintuitive" observation, but raising speed limits may not necessarily make everyone go faster. What it might do, though, is make people more courteous to each other. As an example, if the speed limit is 50mph and you're going 50mph and someone is tailgating you, the fact that they're tailgating you probably frustrates you and makes you less likely to speed up or switch lanes. In fact, depending on your personality, it might make you mad enough to slow down or brake check them. However, if you're going 50mph because that's the speed you're comfortable with, but the speed limit is 65mph, you'll probably still be annoyed at somebody tailgating you but you might also be more sympathetic and hence less likely to do something passive aggressive. This is, of course, all speculation.