backed up
adjective [ after verb ] uk/ˌbækt ˈʌp/ us/ˌbækt ˈʌp/
堵车的
If traffic is backed up, the vehicles have to wait in a long line because there are too many of them.
The traffic is backed up for six miles on the road to the coast. 交通堵塞长达6英里，一直堵到海边。