You can sue the employee and the employer both for your damage, if you believe the employee driver was "at fault" (e.g. driving carelessly) in causing the accident: the driver would be liable as the negligent (careless) or at fault driver, and his employer would be liable under one or both of the following theories as well--1) If the truck was being driver for work/as part of the employee's job, they could be liable under the theory of "respondeat superior," which makes employers liable for the wrongful acts of employees committed in the course of employment;2) The owner of a vehicle is liable if a person whom it allowed to drive the vehicle was at fault in an accident.