FYI - Construction has begun at the intersection of Third Avenue and Prospect Hill Lane (next to the Westin Hotel). See here for more details:

When complete, there will be a new connection from this intersection directly onto Route 128 (I-95) northbound. A new traffic signal will be installed at this intersection, to process the traffic on and off of the highway. Once the new ramp is open, traffic from the office buildings in the Third Avenue and Fifth Avenue areas can access the northbound highway without first crossing Totten Pond Road. This will reduce the traffic volumes at the Totten Pond Road/Third Avenue/Wyman Street traffic signal, which will improve traffic conditions in this area, particularly in the afternoon rush hour. Construction is expected to be complete later this year.