What would most naturally come next in this argument? Everywhere you look, people are commuting in gas-guzzling SUVs. Meanwhile, their backseats are empty all six of them.

This is most likely the starter to a larger argument of the environmental damage that the culture of a car per person creates. So a follow up statement would speak about the gas consumption and emissions of these SUVs and compare them to those of a bus where 20 + people can move in