The city had argued that the ordinance was justified because of the sexual nature of the female breast and because of concerns that bared breasts could lead to distracted driving and harm to children.
I hope they're just suggesting that the distracted drivers might harm children and not that bare female adult human breasts might, because that would be silly.
I really doubt that's what they meant. The concern that viewing a female breast could get a driver distracted is legitimate, but saying female breasts are harmful to children, while it's a societal norm, but I've never heard scientific support for that being harmful to children.