What's behind their name? I figured it was because they started in New Jersey, but I wonder why the name caught on to all of them. Also, what states use them?
Yeah, it's mainly due to the fact that they were developed in New Jersey under research for NJDOT. Apparently, there are several slightly-modified variants for places like California, Texas, and the UK.
Jersey Barriers are pretty widespread at this point. I wouldn't expect that there's any U.S. state not using them to at least a small extent.
We even have them for a few miles in Wyoming, so I can't imagine there's any state without them
Maybe Alaska?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.alaskaroads.com%2FA4%2BAK3-northend-wide-large.jpg&hash=24a021df3772403f9fb585bb9e64ff3e9e46f191)
From Oscar Voss.
Yep, they have Jersey barriers in Alaska.
Nebraska has been using something slightly different looking for the new median barrier on I-80:
http://maps.google.com/maps?hl=en&ie=UTF8&ll=40.840101,-96.738578&spn=0,359.994507&t=k&z=18&layer=c&cbll=40.840037,-96.738644&panoid=UQP3VdV9HIch6htfg_9hRg&cbp=12,144.093916387131,,0,0.6054687500000031 (http://maps.google.com/maps?hl=en&ie=UTF8&ll=40.840101,-96.738578&spn=0,359.994507&t=k&z=18&layer=c&cbll=40.840037,-96.738644&panoid=UQP3VdV9HIch6htfg_9hRg&cbp=12,144.093916387131,,0,0.6054687500000031)
Missouri seem to be using a jersey variant (constant slope?) for new median barriers.
Jersey barriers are also widespread in Europe.
Netherlands:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3329%2F3335134197_0e1697e553.jpg%3Fv%3D0&hash=f2d57c8b39de9ae1a0694f42f373a480243c4f62)
Germany:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3373%2F3214646151_9419c6cab4.jpg%3Fv%3D0&hash=2134ed2d754b77b83cdf97208dc9c33571d76043)
Belgium:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3606%2F3444016567_154faabb99.jpg%3Fv%3D0&hash=9faec6a948de23b42f2b3c6e49be503ca0326bc0)
France:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3505%2F3216210050_4df35f129f.jpg%3Fv%3D0&hash=ead269b19c1f1670f4329a61ffe08bdfdf5d58b4)
Spain:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3477%2F3215539023_cd8d958752.jpg%3Fv%3D0&hash=3298707393ab6e159a70299d9c209e4c6d4a92aa)
Luxembourg:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.static.flickr.com%2F3558%2F3442573144_2cf5ff7327.jpg%3Fv%3D0&hash=06c6ae51d438e896808527d80f153f4bbcd526e6)
I've heard "K-Rail" used a lot in my travels, but never around Ohio or Pennsylvania. I've always called "K-Rail"s the plastic water/sand filled orange/white alternating interlocking barriers.
To me, Jersey Barriers are only temporary. Anything permanent is just a divider/separator/partition/etc.
Sykotyk
According to the Jersey Barrier (http://en.wikipedia.org/wiki/Jersey_Barrier) article at Wikipedia, "K-rail" is the CalTrans specification for temporary concrete traffic barriers.
From my 'growing up in Nevada' perspective, I've always heard "Jersey Barrier" or "Jersey Wall" used for the permanent installation of such dividers.
I've always thought of Jersey Barriers as the permanently mounted barriers used along highways, and K-Rails as the concrete or plastic interlocking ones usually used in construction... and I hear the terms used interchangeably around here.