  This paper is about the general disconnect that we see, both in practice and
in literature, between the disciplines of travel demand modeling and causal
inference. In this paper, we assert that travel demand modeling should be one
of the many fields that focuses on the production of valid causal inferences,
and we hypothesize about reasons for the current disconnect between the two
bodies of research. Furthermore, we explore the potential benefits of uniting
these two disciplines. We consider what travel demand modeling can gain from
greater incorporation of techniques and perspectives from the causal inference
literatures, and we briefly discuss what the causal inference literature might
gain from the work of travel demand modelers. In this paper, we do not attempt
to "solve" issues related to the drawing of causal inferences from travel
demand models. Instead, we hope to spark a larger discussion both within and
between the travel demand modeling and causal inference literatures. In
particular, we hope to incite discussion about the necessity of drawing causal
inferences in travel demand applications and the methods by which one might
credibly do so.
