What is the rhythm of the poem "A Road Not Taken" by Robert Frost?

This poem uses a form of iambic tetrameter, meaning that each line has four "feet." In actuality, what this means is that a person reading the poem aloud would naturally stress four syllables in each line, such that the poem has a continuous rhythmic beat which lends it cohesion. The poem has an ABAAB rhyme scheme, and while there are slight variations in some of the lines (meaning that different speakers might place the emphasis in slightly different places), the stanzas are generally unified by their common rhythm and rhyme scheme.
In iambic tetrameter, the first syllable of each line is usually unstressed, with the next syllable being stressed, and so forth. In the first line of the poem, the stresses would be placed on "roads," "-verged," "yel-"(low), and "wood."