Being a LEO myself. I know in VA they are illegal at night, but are in the process of making them illegal period. There are many things that are illegal down here, that i think should not be. But that's how it goes. Try calling your DMV, or better yet a state police dept. They could look it up in the codes.
They are illegal, but I usually don't stop anyone for them except at night, most don't except for the heavy traffic guys. You can't see for SSSSHHHEEEEEIIITTTTT with them on at night anyhow.