Some of the speed bumps on the main corridors in East Africa have become mountainous to the degree that some trailers cannot get over them.
A friend of mine who’s company specialises in building bridges has a special low bed trailer to transport his equipment. It cannot go over some of the speed bumps that have been built, so they have to go on, quite long, detours to get to their destination.
It would be interesting if someone did a study on the overall economic and ecological impact of speed bumps.