Had I missed this here? Don't recall anyone posting it.
http://www.arlingtontransit.com/pages/news-events/arlington-transit-blog/art-debuting-new-cng-electric-hybrid-buses/ (http://www.arlingtontransit.com/pages/news-events/arlington-transit-blog/art-debuting-new-cng-electric-hybrid-buses/)
ART has buses #5047-5049. I rode #5047, it's a nice bus. Makes up for missing out on the MTA's Designline hybrids.