18x18 shield variants

[Max Rockatansky]

A couple years ago I picked up this 18x18 I-94 shield out of the Mid-West which appears to have been attached to a BGS at some point given it is a thinner gauge:

https://flic.kr/p/SXb2Vq

A new user also has a similar shield with "Illinois"  in the crest.  I didn't see anything on the MUTCD sign chart indicating that smaller shields were a thing presently.  That said did any previous draft of the MUTCD once have an 18x18 shield variant?  The Caltrans MUTCD still has options for small State Highway variant shields which makes me think the Federal MUTCD had one previously. 

[Jacob]

My shield can be seen here:

https://www.flickr.com/photos/182395852@N05/48189680391/in/album-72157709408327732/

I'm trying to figure out it's relative age. I think it may be a 1957 spec? Maybe 1961?

If anyone has any questions on my other signs I'll do my best to answer them.

[roadman]

A couple years ago I picked up this 18x18 I-94 shield out of the Mid-West which appears to have been attached to a BGS at some point given it is a thinner gauge:

https://flic.kr/p/SXb2Vq

A new user also has a similar shield with “Illinois” in the crest.  I didn’t see anything on the MUTCD sign chart indicating that smaller shields were a thing presently.  That said did any previous draft of the MUTCD once have an 18x18 shield variant?  The Caltrans MUTCD still has options for small State Highway variant shields which makes me think the Federal MUTCD had one previously. 

1961 MUTCD allowed an 18" X 18" Interstate shield for trailblazer use.

[Jacob]

What's trailblazer use mean? Is that on a BGS or on a pole?

[csw]

Trailblazers are usually ground-mounted shields located a distance away from the mainline, often with a "TO" placard on top. They help funnel traffic (or "blaze a trail") to an interstate.

[Jacob]

Good to know