차가 막혀요 · 차가 막혔어요 (casual: 차 막혀)
traffic is heavy, to be stuck in traffic
Example
금요일 저녁에는 차가 막혀서 지하철을 타요.
Traffic is bad on Friday evenings, so I take the subway.
Word parts
차 car
Literally 'the cars are blocked'; 막히다 is the passive of 막다 'to block'.
Good to know
Pronounced [마키다] — ㄱ followed by ㅎ becomes ㅋ.