Safety, as measured in fatalities per person per mile per year, has increased by a factor of 100x since the 1960s: traffic increased 10-fold, while fatalities f

Safety, as measured in fatalities per person per mile per year, has increased by a factor of 100x since the 1960s: traffic increased 10-fold, while fatalities fell by the same factor. So they do seem to be doing something right... The lack of chaanges may just indicate that the current paradigm is a rather good one. If anvbody came up with a working scramjet, regulation would be a minor hassle. It's really physics that are limiting here: supersonic travel is too inefficient both economically and environmentally. And personal autonomous local transport (i. e. "flying car") is impossible without some sort of breakthrough on noise.