Recently, my local state highway department put off a US $150-million project because, during a site mapping study, the state engineers discovered a layer of shale under a significant portion of the planned route. Now, building a stable roadway over a large segment of unstable shale is a very expensive and difficult process, so the highway department quietly postponed the project for a couple of years until a better route could be found or more extensive engineering studies could be completed. This was not a popular decision, but it was good engineering.