college melted my brain, life is a pain, and i lack the will to read.
1. Keep the primary tone black
2. Keep your designs consistent, why does the SUV / hatchback have a different decal style in relation to the off-road, van and prowler.
Below are my thoughts on changes that could be done to achieve two different thematic styles, (1 is a more moddern "police style" 2 is monochromatic and can be used to imply that the police force maintains "authoritarian control" role rather than "civil protection".
2.5.1 If you decide to keep the style of the suv / hatchback, i recommend that you add a tertiary tone to either break up *1 or fully solidify *2 the monochromatic style the vehicles currently posses and are poorly executing.
2.5.2 If you wish to keep the off-road / van / prowler decal design find something to fill out the empty space below the white bar (an alternate shade), or find a way to accent the letters that don't know if they want to be white, or black. *3
and lastly:
3. By what authority is this police force operating? Include some sort of seal or crest on the vehicles to prevent them from looking like mall cops vehicles.
*1 : (use either a yellow or some other bright color)
*2 :(use red accents)
*3 :(the first-responder" decal will be difficult to view at a distance, and the "police" cutout on the prowler is poorly defined.)
on a final note, at least you know enough to use the 1.613 golden ratio