This sign is at the eastern terminus of FR181 where it intersects West Jemez Road, near the twin water tanks. The "fine print" verbiage below Area Closed is not easily visible to my aging eyes. I did a double-take to be sure I wasn't breaking the law by hiking here.
I didn't see another sign like this further uphill forbidding motorized travel downhill but I only walked part of the road. FR181, also known as American Spring Road, begins just up the escarpment into the Jemez, off NM4, and winds it way down to West Jemez Road. It gets really rough on the descent; but even so, I've seen vehicles attempting it!