Lowell proposed northern extension. 0.35 miles went out to bid in spring 2021. Phase A (Chelmsford-Westford) was completed in 2009 Phase 2A (Acton-Carlisle) opened April 2018 Phase 2B:(Route 2 bridge) construction started June 2020. West Concord (phase 2C) completed September 27, 2019. Sudbury (phase 2D) has submitted the 75% design and is in the 2022 TIP. Framingham (phase 3) is proposed.