Mission 03: Unstoppable Force
Note: at this point in the game you should have a grenade launcher to make destroying cars easy in chase sequences. This can make this mission pretty easy.
Objective: Take out the convoy before it reaches blume
Hop in the car next to Aiden when the mission starts and head down the road to meet the convoy. Touching the target van should stop the convoy and make them all get out and start shooting. You can also quickly jump out of the car and blow up the van with a grenade launcher, fulfilling this and the next objective.
Objective: Eliminate the target
Back up quickly and run over the enforcer that gets out of the target van (this is your target) and then gun the engine.
Objective: Kill all militia members or escape
It's up to you which approach you prefer (if you have a grenade launcher, taking out the militia vehicles should be pretty easy), but use the same tricks as usual (neutralize points, speed and precision) to finish the objective and end the mission.