Is traffic a countable or uncountable noun?

"Traffic" can be both countable and uncountable, depending on the context.

Here's how:

Uncountable:

* When referring to traffic as a general concept or flow: "There was a lot of traffic on the highway."

* When referring to the amount of traffic: "The traffic was heavy this morning."

Countable:

* When referring to individual instances of traffic: "We encountered two traffic jams on our trip."

* When referring to different types of traffic: "There are different types of traffic: car traffic, pedestrian traffic, and bicycle traffic."

To determine whether "traffic" is countable or uncountable in a particular sentence, consider the context and the meaning you want to convey.