Thank you for calling me out.

What I should have said is more than a mile. Here are only a few that come to mind. What you have to keep in mind is we (SoCal) don't really have bad weather here. So road engineers and city planners don't have to worry about snow or torrential rainstorms and other weather concerns that would make the roads impassable. So they pave roads going to nowhere (dead end climbs we call them) such as water towers, avocado groves and the like.

Los Gatos in Temecula
Decker Rd in Malibu
Balcolm Canyon (don't know what city it's on one of my doubles and the pros do it on ToC)

There are others that are 20% avg over a mile. I have been on them just can't remember their names. And to be honest with you anything over 15% might as well be 20% it's just freakin' hard!