Numbered Highways with the steepest signed gradients

[Max Rockatansky]

One of the side conversations that came about from MMM's disruption of the " Should I-11 be extended over and replace I-19?"  thread yesterday pertained to Signed Highways with steep gradients (see pages 28-29):

https://www.aaroads.com/forum/index.php?action=post;quote=2791425;topic=30826.675

The two Signed Numbered Highways with the steepest signed grades I've encountered are both in California.  CA 4 east of CA 207 approaching Pacific Grade Summit and Ebbetts Pass is signed with a 24% grade warning:

https://flic.kr/p/2jD2Ua7

Whereas CA 108 approaching Sonora Pass is signed with a 26% gradient warning:

https://flic.kr/p/2jD6nJP

Keeping this limited to Numbered Highways what other steep gradients are out there signed in field?

[roadman65]

CA 36 does warn Trucks and RVs that Route 36 is not advisable for them west of I-5.  Though not for a reason, but I assume it's got steep grades in excess of 7 percent that may be signed elsewhere along the aforementioned route.

[Max Rockatansky]

CA 36 does warn Trucks and RVs that Route 36 is not advisable for them west of I-5.  Though not for a reason, but I assume it's got steep grades in excess of 7 percent that may be signed elsewhere along the aforementioned route.

Way more because of 100 plus miles of curbs and a segment which until recently was one lane.