I got a way better idea....and prolly cheaper...
Step 1. Make a new law that if you dont move for an emergency vehicle, you can be pushed off the road.
Step 2. Equip all LE Vehicles with Train Horns from HornBlasters.
Step 3. Equip All LE Vehicles with ARB Bull Bars
Step 4. Give one blast from the horn, if car doesnt move out of the way, Knock there *** into the ditch...
Seriously though, how about giveing them a ****ing air horn? You all know how loud train horns are... And think about this, if the ground shakes......whats gunna happen to the things inside the car....