Make sure that there is enough room to install a car seat by checking the manufacturer’s instructions. According to most manufacturers, a car seat must have at least 80 percent of the base of the car seat supported by the vehicle’s seat, with no more than 20 percent hanging over the edge. Keep in mind some manufacturers require the base of the car seat to by 100 percent supported.
Never install a car seat on a truck’s side-facing jump seat, as car seats and booster seats are crash tested on forward-facing seats.
Under no circumstances are cargo areas to be used as child passenger seating. Children and adults can easily be thrown from cargo areas at even relatively slow speeds. Not only is it unsafe, but it may also be against the law in your state.