Originally Posted by bike_tom

Officially, Phase 2B, the bridge over Route 2, is not open yet, leaving a gap from Wetherbee St in Acton to Commonwealth Ave in West Concord. In reality, it's basically done and folks are using it. I walked from West Concord to Acton, over the bridge, about 10 days ago.
The area south of your photo, from 225 down to Wetherbee St has been open for awhile - I have biked it many times. Took me a bit to understand what I was seeing in your old photo!
Bottom line, you should be able to ride from Powder Mill Rd up to Chelmsford/Lowell, assuming they haven't blocked off the bridge to do whatever work remains.