NYT Sunday crossword puzzle - circled letters and words?

I occasionally take a shot at the puzzle. Last week’s, revealed in this Sunday’s edition of the mag, was titled “Getting Around.” There were a few words in the puzzle, or parts of compound words, that had their spaces circled. The words don’t make any sense to me in any combination I can see, and I can’t figure out what is the significance of these circled letters/words. Not being an expert in crosswords, I figure that I’m missing or overlooking some basic code or plan. Any help, Dopers? xo,

Say, mods, if this is more likely to get responses in Cafe Society, would you please move it there? tx

This blog entry will explain all. (Given here, and not just explained, to link folks to an interesting daily analysis of the NYT puzzle. Check it out!)