tailback
noun [ C ] UK uk/ˈteɪl.bæk/ us/ˈteɪl.bæk/
（路上因受阻而形成的）车辆长队，长龙
a line of vehicles that have stopped or are moving only very slowly, because of an accident or other problem on the road in front of them
Yesterday there was a four-mile tailback on the main road into the city after a crash. 昨天在一起交通事故以后，进城的干道上排起了4英里的长龙。