incident(可数,也可以不可数) something that happens, especially something unusual or unpleasant
accident(可数名词)an unpleasant event, especially in a vehicle, that happens unexpectedly and causes injury or
damage
区别:accident侧重于交通事故产生的受伤。
追答一般情况下,除了固定搭配外,两者一般情况下都可以混用。