Here's another route I explored today; it is the subject of two older threads from 2016 and 2017.
This route runs from I-10 to California SR1 (Lincoln Blvd.), and is mostly commercial on the east end and residential / commercial mix on the west end.
This shows the exit from I-10 West. The '187' shield at the base of the offramp is missing (stolen?)
(https://live.staticflickr.com/65535/50074312707_49d6f4daf1.jpg)
The route sort-of parallels I-10; this older sign still refers to the Santa Monica Fwy. Newer signs just have the shield, direction, and 'Fwy'. The overpass in the distance is the LA Metro Expo Line light rail route.
(https://live.staticflickr.com/65535/50074068411_9d2affba4e.jpg)
The one and only westbound shield I saw was at Sawtelle. It is barely visible on the traffic light mast above the bus. The faded shield on the light pole in the median (far left in pic) is for I-405; the southbound onramp is off of Sawtelle.
(https://live.staticflickr.com/65535/50073501643_1a07c5eae5.jpg)
Just east of Lincoln (California SR 1) is this shield, somewhat battered but intact.
(https://live.staticflickr.com/65535/50073503873_aed173e1eb.jpg)
Did my own CA 187 album today since I was waiting to make a pickup at LAX:
https://flic.kr/s/aHBqjzxWs3
The only westbound CA 187 reassurance shield I noticed was the same as above, probably too high to steal:
(https://live.staticflickr.com/65535/51808956928_89612d8c50_4k.jpg) (https://flic.kr/p/2mWbrU5)IMG_4822 (https://flic.kr/p/2mWbrU5) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
Speaking of CA 187 becoming theft desirable Jake came up with a reproduction:
https://www.ebay.com/itm/353664698209?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Dec24d0eb580a4f7683ef23a07124e54b%26pid%3D100675%26rk%3D1%26rkt%3D13%26sd%3D353664698209%26itm%3D353664698209%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Aeeffe2d1-70f8-11ec-a2d6-e6101423329a%7Cparentrq%3A3ccbdd2f17e0a9d95ec7f722ffd6f5ea%7Ciid%3A1