If you really think that chainsaws are as a big a potential danger as autonomous vehicles are, I have some wonderful seaside property in Arizona I'd like to sell you.

There are lots of wooden bridges out there. A chainsaw will allow you to sabotage such a bridge very quickly, with no visual indication from above. If you do so shortly before the scheduled passenger train comes through, it could be a mass-casualty incident more serious than anything a car could do.