This is the 4213th most frequent Chinese word.
堵车
Traffic jam.
The word "堵车" is used here to describe the event causing the delay, indicating the presence of heavy traffic.
今天早上因为堵车，我上班迟到了。
This morning, I was late to work because of a traffic jam.
In this sentence, "堵车" is used to highlight the conditions on the highway, referring to significant traffic congestion.
星期天下午高速公路上堵车特别严重。
On Sunday afternoon, there was severe traffic congestion on the highway.
Here, "堵车" is mentioned as a possible situation the speaker wants to prevent, indicating planning to circumvent high traffic density.