Emergency Vehicle Turnaround Sign on Interstates

[ethanhopkin14]

This is the furthest east specimen I have found.

[bzakharin]

The new Jersey Turnpike has advance signs for median crossings with inverted C's. I can't find a picture right now. For crossing between car and truck lanes it's a Z symbol like this:
https://www.google.com/maps/@40.2810543,-74.5040493,3a,39.4y,13.37h,87.82t/data=!3m6!1e1!3m4!1s5nmafVkKXZKrjvtBKfxPgQ!2e0!7i16384!8i8192?entry=ttu

[Rothman]

The new Jersey Turnpike has advance signs for median crossings with inverted C's. I can't find a picture right now. For crossing between car and truck lanes it's a Z symbol like this:
https://www.google.com/maps/@40.2810543,-74.5040493,3a,39.4y,13.37h,87.82t/data=!3m6!1e1!3m4!1s5nmafVkKXZKrjvtBKfxPgQ!2e0!7i16384!8i8192?entry=ttu

See hbelkins' post above...

[jeffandnicole]

The new Jersey Turnpike has advance signs for median crossings with inverted C's. I can't find a picture right now. For crossing between car and truck lanes it's a Z symbol like this:
https://www.google.com/maps/@40.2810543,-74.5040493,3a,39.4y,13.37h,87.82t/data=!3m6!1e1!3m4!1s5nmafVkKXZKrjvtBKfxPgQ!2e0!7i16384!8i8192?entry=ttu

See hbelkins' post above...

Here's the NJ Turnpike Example:
https://maps.app.goo.gl/JfpAG5F1UV68qE2f8

The Garden State Parkway, although under the same parent agency with the Turnpike, has a less noted but still unique way of identifying median U-turns using a 90 degree yellow "L" bracket prior to the u-turn area, then 2, 90 degree yellow "L" brackets identifying the U-Turn spot:
https://goo.gl/maps/HvWziWaTvRHet94BA
https://goo.gl/maps/XhXdPCTye44reN957

[thenetwork]

Colorado also uses the black-and-blue paddle signs in the medians for this purpose:

Yes, back to the subject at hand.  Does anyone know what they are called and why is there so much inconstancy across the US about how the emergency vehicle crossover is signed?  The blue and black paddle seems to be a four corners/desert southwest thing only. 

I believe they were "quietly" introduced about 5 years ago in Colorado.  I think they are designed to better warn and designate, for authorized vehicles, where the crossovers are -- especially in night or inclement weather conditions.