Vehicular Ad Hoc Network (VANET) is an emerging new technology and a promising approach for Intelligent Transportation Systems (ITS) domain. Many researchers focused on the creation of reliable, scalable and efficient routing protocols for VANET and improve their Quality of Service (QoS). Communication among vehicular nodes which enable drivers to take appropriate decision needs a high reliability, therefore the design of a routing protocol that ensures a certain level of QoS, represents one of the most important challenges of the vehicular networks, because VANET are characterized by specific features, such as restricted mobility, high node speed and a very dynamic topology. keeping in view of the above, this paper provides a detailed description of various existing QoS routing protocols in literature with an aim to classify them. Based on the optimization methods used to improve routing protocols in VANET, we have surveyed and classified the routing protocols into two classes, QoS routing protocols not based on meta-heuristics and QoS routing protocols based on meta-heuristics.

车载自组织网络（VANET）是一种新兴的新技术，也是智能交通系统（ITS）领域的一种有前途的方法。许多研究人员专注于为 VANET 创建可靠、可扩展和高效的路由协议，并提高其服务质量 (QoS)。使驾驶员能够做出适当决策的车辆节点之间的通信需要高可靠性，因此确保一定水平的 QoS 的路由协议的设计代表了车辆网络最重要的挑战之一，因为 VANET 具有特定的特征，例如受限的移动性、高节点速度和非常动态的拓扑。鉴于上述情况，本文详细描述了文献中现有的各种 QoS 路由协议，旨在对它们进行分类。