If a machine is fitted with an overhead guard, as both counterbalance and articulated machines are, then it is essential that the operator is always restrained by a restraint system whilst on the machine. The restraint works to ensure that, in the event of an overturn, the operator does not become trapped or crushed by the overhead guard. If a truck overturns, and the operator is not restrained, the operator will be thrown from the seat and almost certainly injured, or worse, by the guard which is designed to protect him from objects falling from above and therefore very necessary.