I thought of something similar to this years ago. I also came up with an LED set that would give advance warning of slowing and stopping, including a display of the truck’s speed-so folks could see that he was actually slowing and at what rate.
After fixing a 101 set of LED’s on the door of the trailer, I ran a multiplex cable up through the 9 pin pigtail, and into the cab. Then I connected them to the data link, which will work on any vehicle equipped with a J1587/J1708 diagnostic data link, and a direct connection to the brake light switch with an electrically actuated rheostat.
It worked pretty good, right from the jump. Only one big problem. My buddy got a ticket for unauthorized lighting equipment and disallowed color of light bulbs.
Seems the FMSCA regs only allow lights to be:
Front: White and amber
Sides: Red and amber
Rear: Red, amber and white.
And the DOT loves to write tickets.
I think a better approach for this company would be to have wireless cameras and cars to to have the ability to display those on their dash monitors that are currently used for GPS and vehicle information.

