May Swenson is one of my favorite poets. "Southbound on the Freeway" is a poem of 13 stanzas (a group of lines in a poem) of two lines each. It's written in free verse because it doesn't rhyme or have a particular pattern of rhythm. The speaker in the poem is an alien from another planet who has come to visit Earth. You'll notice there is no punctuation at the ends of lines, but instead, Swenson uses important words at the ends, a technique known as enjambment.
Now to what it must mean. As I said earlier, an alien from another planet, Orbitville, lands on Earth. He/she is shown to be naive, totally unaware of what humans are about. The alien's perceptions of Earth demonstrate the theme of technology versus human intelligence. Written in 1963, technology was nothing compared to today, but the poem deals with Americans' love for their automobiles. The underlying question Swenson wants us to answer is, "Are humans still in control or are we just trying to hang on for the ride?" Do our machines control us, or are we still in control?
The first things the alien notices are the cars that people are driving. He/she/it thinks the cars are the creatures of this planet, however. Cars and trucks are the dominant objects the alien sees, so he/she/it is confused. The alien even notices that some of the cars are "special" (police cars and ambulances) since the other cars slow down or move aside to let them pass.
At the end of the poem, Swenson moves to the question of what our purpose is as human beings. Are we the "guts" or the brains of the cars in which we ride? Of course, our brains created the cars, but we were then (1963), and are more so now, dependent upon them. Swenson questions how much power we have given to our creations. "Brains" implies intelligence in the poem, while "guts" implies courage. In the end, this poem asks us whether human creation is a question of courage or of intelligence.