A couple of weeks ago, they put an automated speed sign up just past where my accident was. It is one of those signs that tells you that the speed limit is 30 and then tells you how fast you are going. They took the sign away yesterday. I'm sure the sign makes a difference while it is there, but I wonder if it makes any difference once it is gone. Because there are no consequences, is suspect that this has less of a long-term impact than a speed trap. With a speed trap, it comes and goes and people don't want to pay a fine. I'm sure people don't want to be reminded that they are speeding, but when they are not being reminded, they don't care. With the speed trap, some people will get to know that speed traps are sometimes in that area and make an effort to slow down at least for a little while.
In our neighborhood, they built some new houses and widened a road nearby. The speed limit remained 25. A couple of years ago, they regularly had speed traps there although they are rare now. I don't know if the speed traps had a lasting impact, but I think people slowed down for quite a while after they were gone. I'm guessing that by next week, any lingering effect of the automated speed sign will be gone.