The details of this poem are so unassuming that they may easily be missed. The young woman is not in a negligee, she is "in negligee." One also must do a sort of double-take to figure out how the speaker could know this if she is behind the walls of a house. Though the standard line on Williams is that he freezes moments of perception (language used to render perceptive instants), this poem, while apparently simple, utilizes a three-part temporal framework. The first stanza describes a moment when the speaker passes "solitary." Is he on his way back in the second stanza which begins "Then again . . ." or is this possibly a fantasy on his part? In relation to the only, self-consciously stated, image: what are we to make of the implicit connection between the woman as a leaf and the leaves crushed by the car's wheels? Is the woman something crushed or discarded? All of these questions, as well as the implicit motion of the speaker who is driving by in a car, tend to place the interlocking phrases and descriptions in a kind of metaphorical suspension. Underlying this suspension of what is, after all, a small drama, has to be the speaker's unstated desire for the woman. Once again, the poet's desire structures the details, progress, and interrelation of elements in the poem.
from Modern Poetic Practice: Structure and Genesis. New York: Peter Lang, 1986.