Deirdre Fernandes at the Globe reports today on design plans for the final stage of the 128 add-a-lane project, which will add a fourth lane to the highway in Needham and Wellesley, replacing a temporary breakdown lane which has been in place for almost a decade.  The project goals are to improve safety of interchanges and traffic flow on the aging highway and to keep the highway traffic off local roads. Significant changes have been made inrecent years to the path of the highway itself as well as to the collector-distributor roads intended to reduce conflicts and thereby prevent traffic backups.  Sound barriers have been added to help abutters.  Feedback from bicycle and pedestrian advocates have had some impact and are still under consideration.  But proposals for a new exit at Kendrick Street and signals to partially replace a cloverleaf interchange at Route 9 are among changes causing the most consternation, particularly in Newton.

At a recent forum hosted by the Newton Needham Chamber of Commerce, state officials were confident that the new signals on Route 9 would function well, based on their simulations.  Unlike full signals, they reasoned, these signals only pause traffic briefly for left turns and only for those turns with the least demand.  Changes were being considered to address merging traffic from the Wellesley Office Park, but were not yet ready to be discussed.  Further to the south, perhaps some good news for Needham: turn restrictions were added to the new Kendrick exits to keep traffic flowing directly to office parks rather than through streets like Greendale Avenue, and a flyover ramp will provide increased capacity and direct access onto the highway, rather than through the C-D road.  A win for business development and hopefully for residents as well.  But what are the consequences for Newton?  Would motorists seeking to avoid congested routes like Needham Street or Route 9 use the new Kendrick exit to cut through Winchester or Dedham Streets?  Would there be significant impact to regional traffic patterns for access to towns like Brookline, Watertown, Boston and Cambridge from 95/128?  Not so, said the state officials, who said their models did not show any such problems.  What options does Newton have if they’re wrong, besides adding infrastructure to accommodate the increase in demand?