To all the MD EV owners, I just got a replacement/renewal HOV sticker through the mail last week. Prior legislation had the HOV EV allowances set to expire next month. It was apparently updated back in May, and now we're good through 2022! This was such a relief for me, since US-50 takes up 1/3 of my daily commute. I actually had a reminder on my phone to call the MVA in a couple of weeks to ask about this specific issue.
http://mgaleg.maryland.gov/2018RS/bills/hb/hb0714f.pdf
http://mgaleg.maryland.gov/2018RS/bills/hb/hb0714f.pdf