MoveThatPed

Turns your real microphone into a working police megaphone in GTA V. Speak into your mic and the game reproduces it through a megaphone-shaped DSP chain; say "move," "clear the road," or "pull over" and AI traffic physically reroutes around your unit.

Free, closed source, and distributed only on LCPDFR.com, which is where the button below takes you. Requires RAGE Plugin Hook, LSPDFR 0.4.9+, and a working microphone.