American Fugitive

This is one of the more agitating achievements in the game. It doesn't seem like you can run over any vehicle that's bigger than a normal police car. It is also very easy to get stuck on top of a car. I found the best farm for this was roll around in a tank and watch for police cars. Once there were too many destroyed vehicles in the way, i'd either save and quit to despawn the debris, or let myself get arrested to clear the debris.

Once you have access to buying a tank, roll around in it. As your wanted level increases, tanks will begin to slowly spawn. You can find them after hearing a notification on the radio saying a tank is on the way.

You can keep track of how many tanks you have killed on your statistics page in game.

Easily accomplished in the time trial - Pink Doc Dash - in the second area.

Start the time trial, keep boosting till you explode. You should be going fast by the time you explode.

Easily accomplished using the Astro ZX car (2nd row, 5th column on the phone).

Needed the armadillo (dune buggy) for 1 jump in the 2nd area. You jump onto a boat and then you have to jump off. The armadillo has enough acceleration to get you off.

Best spot i found is on the first island. Go to the challenge - Property is Theft on the west side of the map.
You start with a tank. Turn right at the start, there are two parking lots with 5-6 cars. Police cars should start swarming you.

Finish the challenge and restart it till you get the achievement.