Here's a pair of street signs I spotted in Yanshui, Tainan County, the other day. I've never seen Wu (which here means 'martial' or 'military') spelled this way in any other part of Taiwan. Foreigners have bemoaned, lamented, ranted and raved about the mess that is romanisation in Taiwan... the way governments have adopted one system and then, a few years later, another... and the sad truth that many signs aren't proofread before being put up. It's sometimes a major problem for visitors who can't read Chinese and don't know that Zhongzheng is the same as Jhongjheng or Jungjeng or Chungcheng.
If you want to learn more about the issue, visit this excellent website: pinyin.info.