Vehicular communication assists the drivers to take appropriate reliable decisions on time and preventing hazardous situations. The decision-making depends on the reliability of the received safety messages. The QoS routing protocols provide a certain level of QoS in data transmission and maximize driver-s decision-making efficiency. However, the highly dynamic VANET environment makes the QoS routing a challenging task. Numerous QoS routing protocols are available in the literature, and they are classified into Meta heuristic-based and non-Meta heuristic-based