On the night of Monday, July 27, 2015, Phil Schanbaum stopped his car on a busy highway and had his friend snap a picture. The picture shows him in front of a digital changeable message sign. The sign was warning, or advising, or congratulating travelers with this message:
Schanbaum posted the image to Instagram, where social media picked it up.
Brandon Formby of the Dallas Morning News wrote a blog post and tweeted about it. He interviewed highway officials, who disapproved and suggested the culprit was someone accessing an unlocked control box.
Hacking these signs does not appear to be too difficult or too uncommon. Other popular messages have included "Raptors Ahead," "Nazi Zombies, Run!" and "Klaatu Barada Nikto." There are websites that purport to tell you how to hack the sign and offer "The 25 Funniest Hacked Traffic Signs Ever." In a selfless act of public service, a Russian gentleman went to jail for hacking a sign to show porn videos (NSFW).
"Deez Nuts" is an Internet meme that experienced a recent revival. However, The message "Deez Nutz" does not display pertinent traffic operational and guidance information and so would not be appropriate under federal operational guidance.
Melih Abdulhayoglu further suggested that these signs are vulnerable to malware as well.
The issues here are clear:
Highways are critical infrastructure, and to the extent they can operate smoothly, they need to.
The signs serve a purpose, and altering them removes what may be an important safety or advisory message.
Somebody could get hurt.
To perform the physical hack you have to get out on the highway where the safety problem already exists, exposing yourself to raptors or whatever the problem may be (see above).
It may screw up the programming in the sign, and your tax money has to pay to get things back to working order.
The moral: have a good laugh with Phil, but keep deez nuts to yourself.