Difficulty: Easyish
Chapter 2-1 introduces your first truck driver, but he's hard to hit with the early game weapons.
Chapter 2-3 has two more drivers, with the second of these being easiest to hit. Shoot the door off and you'll have a much easier shot at him. Using pistols or machine guns are good options, shotguns are not.
Note: Shooting the red barrels stops the trucks but won't give you the trophy.