The various levels of police action are as follows:

Level 1: Marked patrol cars and cruisers. They mostly chase and try to run you off the road. If you have a quick car, they are not hard to get away from.

Level 2: Unmarked patrol cars and cruisers, roadblocks. The police mainly try to ram you off the road and setup roadblocks. Avoid roadblocks by doing an emergency brake lock U-turn or go through them. You can get through by ramming the cars on either end of the roadblock or by going through a weak point like the sawhorse or a gap between the cars. Use Speedbreaker to see the weak point in the roadblocks and use nitrous to ram straight through. Some road blocks will not extend all the way across the road -- you can go through where they have not placed a car.

Level 3: Marked GTO (Monaro) police cars, marked 4WDs (Rhinos), rolling road blocks, roadblocks. These are quicker and you need to use objects to knock down in front of them to disable them. Lead the chase with these vehicles through the cities to use knock down points (for example, the giant donut sign, etc.) to disable the vehicles and end the chase. Then, find somewhere to hide when you hit Cool Down mode. Rhinos will ram you from the front. Listen for the call over the police radio. You can usually see these coming on your map or on the road ahead. Depending on which car you have, you can get away with ramming them head on. Otherwise, just use Speedbreaker again to change lanes before they ram you.

Level 4: Unmarked GTO (Monaro) police cars, helicopters, spike strips. The unmarked GTOs (Monaros) usually chase in packs and are very hard to avoid. They will try to box you in by surrounding the car from the front and back and slamming the brakes to take away any room you have to escape. Avoid this by staying ahead and using the same tactics used in level 3. For the helicopters, use tunnels and underground parking lots to escape from them. When they spot you, they can radio the police to your location. Spike strips are set up usually on main roads and highways. You can see them on the map when you see only one vehicle over to left of the road not driving (i.e., pulled over). Aim for the police car and use nitrous to ram it and get away. If you hit the spike strip you will get caught.

Level 5: You will not reach this level until you are at Blacklist #3. When you reach this level, all the best and toughest police come out. The helicopters get more aggressive, there are more spikes, and more belts are called in on you. You must also deal with cross cop Corvettes. Cross and his team will apprehend you at all cost. Like in level 4, the unmarked GTO cars will surround and box you in and hit the brakes. Corvettes will also try to use rolling road blocks. If you reach level 5, make sure you are in your fastest vehicle. You will need the nitrous.