Interesting. I thought there was local opposition along the corridor east of I-95 to improvements, despite the crash history. Something along the lines of encouraging traffic and ruining rural nature, blah blah the usual.
The proposed improvements were to be W of route 128, (mainly Concord). 128 now has the dual 128 / I-95 label. State Route 2 had been upgraded to freeway from 128 eastward to another infamous rotary in the mid to late sixties. Six and eight lane cross - sections. The enormous trenched facility in the Belmont/Arlington area, with parallel frontages shows the scope of what was supposed be one of the main radials extending outward from downtown Boston.
The section W of 128 became ever worse, with it's undivided four lane profile, sub-urbanization, gentrification, and growing traffic loads. It featured a steady death toll, until a band-aid in the form of a center double faced Jersey barrier was erected sometime in the nineties. The more recent mainline 2 bridge replacements at the 2/128 cloverleaf, and the crosby's corner intersection re-do both appear to be of lower standards, with the 2 alignment shifted at the cloverleaf, and the crosby's interchange not of Interstate standard.
The failure to act, in the early to mid seventies, when it was cheaper, and far easier to do, illustrates the impotence of both the Sargent and then Dukakis administrations. The six lane cross - section, interstate grade with grassed median, in Lexington, E of 128, should have been extended all the way W beyond the Concord rotary / Reformatory Circle to the split of state route 111.