Bill Geary of Quincy wrote to ask about backups around the Neponset River Bridge ­reconstruction. He’s not the ­only one wondering. Those stuck in recent weeks trying to get to Boston from the South Shore have fumed on Twitter, Craigslist’s “rants and raves” section, and blogs such as ­Neponset River Bridge Dig , which tracks the progress of what some locals dub “one of the biggest traffic headaches since Boston’s ‘Big Dig.’ ”

The bridge carries 61,000 to 71,000 weekday vehicles — for perspective, that’s about three times the volume on the ­Longfellow Bridge — on Route 3A between Quincy and ­Boston. On the Boston side, it meets Neponset Circle and feeds the Southeast Expressway, also known in that stretch as Interstate 93, US Route 1, and state Route 3.