I'm the Autobahn you're a cul-de-sac
Autobahn are highways in Germany. They have no general speed limit and are very long and wide.
Cul-de-sac is an expression referring to a dead-end street with only one inlet/outlet.
The former has a lot of vehicle traffic i.e. a lot of things are going on, while the latter is used to calm down vehicle traffic. Lupe is saying that he’s very open-minded and his lyrics aren’t limited to one subject matter or two. This isn’t the case with a lot of other rappers, who only talk about money or girls. The “lot of traffic” part alludes to the fact that there are a lot of things going on in Lupe’s lyrics. His metaphors density is ridiculous and that adds a lot to the content. Those other rappers though, have simple lyrics that can only please teenage girls.
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