《礼记·曲礼上》
车子开动以后，负责警卫的车又急忙跟在车后。车子走到大门口，国君按住仆人的手，示意停车，并回过头来命令车右登车。车子经过城门、里门和沟渠时，车右必须下车步行。
至于大门，君抚仆之手而顾，命车右就车；门闾沟渠，必步。
After the carriage starts moving, the carriage responsible for guarding it should immediately follow behind. When the carriage reaches the main gate, the ruler should press the servant's hand to indicate that the carriage should stop, and turn his head to order the charioteer to get into the carriage. When the carriage passes through the city gate, the inner gate, and the moat, the charioteer must get off the carriage and walk.