This is the place to post questions and discussions on usage and style. The members of the Wordwizard Clubhouse will also often be able to help you to formulate that difficult letter.
The "go-to" phrase on our local news stations seems to be "traffic congestion". They talk of certain areas of the city that are congested. Another phrase is "heavy traffic". When traffic is moving slowly because of volume (usually the morning commute to work or the evening return from work) it can be said to be creeping or crawling. The most aggravating kind of traffic is the kind where you are stopped in the road for several minutes. Just as you are considering shutting the vehicle down, the line moves forward a few car lengths and then stops again. Rinse and repeat. This is called "stop and go" traffic.ACCESS_POST_ACTIONS