Honestly, if you're in the city, it's kind of easy to get rid of the cops. Use that mini map. It shows you where the cops are coming from. You can't just hit a straight-a-way and outrun 'em, cause their cars are faster than yours, and they'll keep ramming the shyt outta you. If you don't wanna get out and hop fences and shyt, then just hit a couple side streets until they lose sight of you. Then pay attention to the map, and wherever you see the blue & red dots, go the opposite direction.
The most trouble I had with the cops is when I stumbled on some human research base (
),
and I was on an ATV. Hit me with instant 4 stars, and they sent the wolves out after me. Didn't last 5 minutes.