When something that literally anyone in the world can access says "DEATH MAY OCCUR !!!" it's generally a good idea to build some kind of security around it.
Oops - no. For some reason, someone thought it would be a good idea to put traffic light controls on the Internet. Making matters way, way worse is that these controls require no login credentials whatsoever. Just type in the address, and you've got access.
You'd have to know where to go looking, but it's not rocket science. Security penetration tester Dan Tentler found the traffic light controls using Shodan, a search engine that navigates the Internet's back channels looking for the servers, webcams, printers, routers and all the other stuff that is connected to the Internet.
Once the controls were brought up on a Web browser, anyone could put lights into "test" mode. Seriously, do not try that at home.
Tentler declined to say which city put its traffic controls on the Internet, but he notified the U.S. Department of Homeland Security about it.
Shodan is an Internet search engine capable of finding just about every connected thing imaginable.