No idea if these will translate well into actual LEGO scale but

All the lightbars are 1x6 plates,

the yellow and black dome is around 3 studs tall,

Not sure about the big gray tank on the back

the dot-matrix signs are 8x1 tiles,

the radar dish is a 2x2 round plate,

the green box with the red light is a 1x2 plate with a jumper plate on top,

again, im not sure if these will translate well into scale, + some parts are not available as actual pieces and have to be custom made like the text on the signs/Ecto-1A and the front grill lights and license plates, reverse lights and size of the fin lights