Tom nie musiał brać taksówki. Mógł się przejść.

English Translation

Tom didn’t need to take a taxi. He could have walked.

can przejść się be considered an equivalent expression to iść na pieszo? Or is it that just in this particular sentence, because of context, przejść się is associated with walking, as opposed to moving using any other means of moblity?

In this context, “przejść się” is indeed pretty much equivalent to “iść na pieszo”. I feel like “iść na pieszo” would sound more natural here though.

“Przejść się” usually has connotations of “walk leisurely” or “take a stroll”. In colloquial language, it’s often used interchangeably with “iść”.