If this is as easy as i-hacked.com says. Changing an electronic construction road sign is easy!
"1. The access panel on the sign is generally protected by a small lock, but often are left unprotected. Upon opening the access panel you can see the display electronics.
2. The black control pad is attached by a curly cord, with a keyboard on the face.
3. Programming is as simple as scrolling down the menu selection to “Instant Text”. Type whatever you want to display, Hit Enter to submit. You can now either throw it up on the sign by selecting “Run w/out save” or you can add more pages to it by selecting “Add page”
** HACKER TIPS ** Should it will ask you for a password. Try “DOTS”, the default password.
In all likelihood, the crew will not have changed it. However if they did, never fear. Hold “Control” and “Shift” and while holding, enter “DIPY”. This will reset the sign and reset the password to “DOTS” in the process. You’re in! "
I want to make one say "WTFOODGE!!!" But I'd probably go to jail for that and it'd probably trace right back to me since I just said in the last sentence that I wanted it to say Wtfoodge.