Did they try other alternatives, like reflective tape? Wrap it around like handlebar tape. Make it degradable or else the woods will fill up with junk.
Let's brainstorm some more, design a special hunter-seeker robot powered by AI that captures deer in the wild and performs this menial task.
Thank you, I'll show myself out.
Put a tiny radio on all of them that broadcasts a “deer here” signal, and require cars to have a receiver to detect them. Ideally, make it a RFID.
You seem to have forgotten to take your comment out with you.
Bio-engineer the animals so their antlers and/or fur becomes reflective itself, and / or glow in the dark.