I'm an average-sized male using correct for me 40 cm (center-to-center) bars and I have my brake/shift levers marginally turned in for comfort, they're already 28 cm inside-to-inside, and so not permitted by the UCI. Smaller men and average women are completely left behind by this rule, and I (and many others) question the efficacy of it—the crashes I've seen and been in I didn't think that steering authority was the limiting factor. At best it won't do much, at worst it will encourage riders to find other ways to get narrower which involve getting their hands off the brakes; there's a cyclist who's well-known for riding with her hands on the fork.