Watch Dogs
49 Achievements
1,250
Free Radical
Escape a level 5 police chase
30
How to unlock the Free Radical achievement in Watch Dogs - Definitive Guide
To get the attention of the police, you'll first need to cause some trouble. So start off by pulling your gun out on some civilians and shooting them. At some point during this, a random civilian will call the police to your location. Once that call has been made, the police will then set up a scan area to find you which will be shown on your mini-map by yellow circles. Simply stay in this circle until the percentage timer next to the police level bars in the corner reaches 100%. At this point the bars will change from yellow to red and you'll now be a wanted man. After the police are on you and if you're at level 5 wanted level, simply cause more chaos and death until you are.
Everything now is down to how well you can escape and use your hacks to get away from the police. You'll have cars, trucks and helicopters after you, so you'll have to be fast. Using hacks like blockades, gates/doors, bridges and traffic lights will help slow the cars down. If you've upgraded your Skills, you can even hack the helicopters to bring them down.
If you're having trouble doing it this way, I suggest you use the tactics given by PowerPyx but shown by Maka's video below. Once you've managed to escape the view of the police, either keep driving or hide in a garage until your wanted level returns to normal. Once the search is off, the achievement will unlock.
The level 5 police chases are not for the faint of heart. You will have helicopters tracking you from above and they will be sniping at you. You'll also have armored policeman and a relentless number of squad cars coming after you.
You will need to build up to level 5 first. The best way to do this is by getting at least a level 4 wanted level before the police start coming after you. A good place to do this is outside Navy Pier. There are many civilians walking around (especially during the day time). Start shooting as many of them as you can and try to take out any that are calling the police. Your wanted level will rise quickly before the cops are even after you. If you're worried about reputation, just allow yourself to die and you'll respawn with your reputation back to where it was since the game at no point auto saved.
If you do this outside Navy Pier, you can enter the coffee shop nearby and pick off police with your guns and toss grenades or IED's outside the window to build up your wanted level to level 5. They won't enter the shop. You will need to make your escape after you get to level 5. You have two options. If you have a fast car nearby, you can try to outrun them. The method I found very easy if you did this in the coffee shop is to exit the back door. All the cops are out front and if you exit the back door and run left to the lake, there will be a boat waiting for you. Hop in that and the only thing that can track you is the helicopter, you can take care of that by using disabling the helicopter (if you have purchased that skill) or shooting the sniper. Once you have control of the boat, just drive out to sea. Alternatively, if you manage to get to a train, disable the helicopter and board the train. Instant getaway.
Neosnake mentions a fairly easy way if you tie it to a specific Fixer Contract.
There is a Fixer Contract called Armored Pursuit, which is a Getaway Contract in The Loop. You are left with a level 5 heat when you complete it, so it could be a better option instead of killing cops and lower your reputation. You can simply initiate a police scan near the train by shooting the ground and escape when chase starts. Just disable the helicopter before boarding and police on the ground won't be able to see or find you.
To see the coffee shop boat plan executed, watch the following video: