Vulnerabilities allow anyone to take complete control of the devices and send fake data to traffic control systems. The devices are also used in cities in the UK, France, Australia, China, etc., making them even more interesting. Anyone could cause a traffic mess by launching an attack with a simple exploit programmed on cheap hardware ($100 or less) I even tested the attack launched from a drone flying at over 650 feet, and it worked! An attack could be launched from up to 1 or 2 miles away with a better drone and hardware equipment.”]
Source: https://ioactive.com/hacking-us-and-uk-australia-france-etc/