21453. (a) A driver facing a steady circular red signal alone shall stop at a marked limit line, but if none, before entering the crosswalk on the near side of the intersection or, if none, then before entering the intersection, and shall remain stopped until an indication to proceed is shown, except as provided in subdivision (b)
你的理解是最后一个分句把整个(A)都except过去。
21453. (a) A driver facing a steady circular red signal alone shall stop at a marked limit line, but if none, before entering the crosswalk on the near side of the intersection or, if none, then before entering the intersection, and shall remain stopped until an indication to proceed is shown, except as provided in subdivision (b)
这是你的个人理解,但是在statute interpretation下,当一个条文有多个解释,法院将采取最合理的解释而不是采取不符文理的解释。
尤其是(b)规定: after stopping as required by subdivision (a), 里面说了stop, 表示制法者的原意是我第一个解释, 而不是你的解释。就是说(b)也是要按(a)的要求停的。
en.wikipedia.org/wiki/Statutory_interpretation