traffic是可数名词还是不可数名词

Traffic双语例句：

We should do something about the traffic problem.

我们应当对交通问题进行整顿。

There was heavytrafficon theroads

道路上车流拥挤。

Air traffic had returned to normal.

空中交通已恢复正常。

Traffic is now flowing smoothly again.

现在，交通又畅通了。