By virtue of the original post and the disagreement in the comment thread, I think we see that the sign is not clear. Many people think it is a total ban on parking except that you can pickup/drop off for 15 minutes during the day. Other people think it means parking is always allowed, except it is limited to 15 minutes for pickup/drop off during the day. I am in the latter camp, by analogy to the commercial and valet zone signs found around the city.