If you are getting beat up by the swarm of cops that come out in full RIOT, go to the garage and park. The RIOT will be turned off. To save your progress, you will have to pull into the garage again
Stay by your garage and induce a RIOT by killing the civilians and other gangs on the street. To get the RIOT factor up faster, blast away the street cops. When your armor is running low, drop by the garage and pick up a repair kit. Keep repeating this until you get enough money for the upgrades. If you 'fail' the RIOT, do not restart by loading the previous save. This allows you keep all the money, no game penalties will be levied, and you will keep all of your upgrades. The only thing you will lose are all of your weapons.
When you progress enough, you will be taken to another city by following the 'M' on the map. You can actually go back to the previous city at anytime. Pay attention where the exits are for the cities.
To get tornado Press Y, B, A, X, X, A, B, Y on your controller.
First press the START and at the map section and then press Y,B,Y,B,X,A,X,A,Up,Down.Then you will hear a engine sound.It increases your money by 100000.
RoadKill Cheat List
Pause the game and enter any one of these codes at the map screen:
All guns: Y, A, A, Y, X, B, B, X, A, X, B, Y
Decrease Riot Level: Y, B, A, X, Y, B, A, X, DOWN
Increase Riot Level: Y, B, A, X, Y, B, A, X, UP
Infinite Ammo: Y, X, X, B, Y, X, X, B
Money Cheat: Y, B, Y, B, X, A, X, A, DOWN, UP
Restore Health: X, B, X, B, X, B, X, B
Tornado: Y, B, A, X, X, A, B, Y
First pause game, then go to map option and put in Y, X, X, B, Y, X, X, B.
Press Start to pause game play and highlight the 'Map' option. Then, press Y, A(2), Y, X, B(2), X, A, X, B, Y. The sound of an engine will confirm correct code entry. You still need to find where the original weapon power-up appears, then collect it again. It will also cause some weapons which you have not unlocked to appear next to your garage. However, not all weapon power-ups are next to your garage. They are usually nearby, but on a ledge or around the block.