Olive drab. Try XF62, but you'll have to put a clear gloss over it. Strangely enough, no one makes a gloss olive drab.
MSP actually paints their cruisers the same colors the army would use to camoflage a battlefield tank-for the same reasons. They can be surprisingly hard to pick out when stopped beside the road. But they're all well maintained and are almost always clean, so both the black and olive drab are gloss.
Why an MSP cruiser?