because I'm pretty sure Traffic Jam in german is not 'Verkehr Marmelade' (me literally translating that...)
Haha! A "traffic jam" is ein Stau. It's a masculine noun but has some disagreement over the spelling for the plural and other cases.
You often hear on the German radio traffic reports "Ah-acht (A8) Richtung Stuttgart zwischen Pforzheim Nord und Pforzheim Ost, drei Kilometer Stau" and so on.
Not really in this sentence. "Traffic" is only used for traffic in computer networks or on websites. (In which case you probably wouldn't use "slow" in English).
The German word "Traffic" is only used in computer contexts, for traffic on a road you have to use "Verkehr".
"Traffic" (Verkehr) can be moving or stationary, free-flowing or congested. A Stau ("traffic jam") is only slow/stationary and congested. The traffic is slow through a village centre, but not necessarily because of a Stau.
but ein stau does not refer to this traffic really, right? It is a traffic jam, whereas this traffic, der verkehr, is just generally the amount of cars on a road, and can go fast or slow?
When used as a noun, "der Verkehr" means traffic. http://en.pons.com/translate?q=Vehrkehrl=deenin=lf=de http://dictionnaire.reverso.net/allemand-anglais/verkehr
The verb "verkehren" does have a conjugation that looks like the noun and means "go", or "run" in the sense that a train or bus runs, or fly in the sense that a plane does. It is an imperative form, but I think people would probably use a different form to avoid confusion. http://en.pons.com/translate?q=Verkehren=deen==de http://dictionnaire.reverso.net/allemand-anglais/verkehren