House numbering on Pacific Coast Highway?

Apologies if this is a tad off topic for this group, but I'm unsure where
better to start asking!

During a trip to Southern California earlier I drove a short way on the
PCH between Santa Monica towards Malibu was puzzled by the house numbers.
Some online research yesterday has only confused me further. Here's an
illustration I've prepared of a random stretch of properties on the beach
side of the road, going north:

http://dl.dropbox.com/u/4019461/HouseNumbers-1.jpg

I gather the numbers are in groups, often based on the distance from some
base, or on the number of blocks. So I can just about see how that
accounts for such large numbers. But can anyone please explain why the
gaps between adjacent houses are not simply 2, instead of 4, 6, 8 or 10 -
not to mention 34? I can't detect any logical pattern at all!

--
Terry, East Grinstead, UK