The state did a route designation cleanup back in the 1960's, but hasn't done much of anything since besides reshuffle the inside-128 designations to stretch around the canceled highways. Well...and continue their jihad against letting 128 be 128.
These are by far the most useless in Boston area:
-- MA 3/I-93 concurrency, Braintree-Leverett Circle exit. SE Expressway and tunnel already carries Route 1 as a triple concurrency, and the Expressway hasn't been 3 since the 60's. Get rid of it.
-- MA 2 on Fresh Pond/Memorial/BU Bridge/Mountfort/Beacon/Comm Ave. Seriously...who would ever follow a set of directions from Lexington saying "take Route 2 to the Public Gardens garage." Truncate it at Alewife. Extend US 20 down Comm Ave. to the Gardens so 20/9/28--3 routes that span all or most of the whole state--all converge more or less logically on one block.
-- MA 3/US 3 in Cambridge-Boston, 2A Lexington-Cambridge. US 3 currently goes down Mass Ave., up to Alewife, down Fresh Pond Pkwy., down Memorial...then magically changes into MA 3 at the Mass Ave. underpass...then goes over the Longfellow...then down Storrow...then Leverett Circle into the I-93 concurrency. Jesus...just keep it on Mass Ave. all the way, send down Memorial, and keep going to Rutherford Ave. and that interchange. Delete 2A after Mass Ave. where it starts making turns on 45 different streets in Lexington and Arlington. People only care about the cut-over from 128 to Mass Ave.
-- US 1/I-93 concurrency. Get rid of it. Nobody cares about interstate concurrencies except 128. Put it back on its thru route to Boston. If you absolutely "have" to connect something via the Expressway, make it 1A...which makes absolutely no sense in its current now-you-see-it-now-you-don't configuration on either end of town.
-- 128. For the love of @#$%, put it back to Braintree split. EVERY traffic report in the morning calls that stretch of 93 "128". Stop bucking public sentiment.
-- MA 203. Currently fizzes out at the Centre St. rotary. Keep it going down Jamaicaway/Riverway/Park Dr. so it forms a belt-parkway from 93 to Comm Ave./US 20. That's a route people actually use.
-- MA 4/MA 225 concurrency, Bedord-Lexington. Pick one number and stick with it. Both routes spend nearly half their length concurrent, and for all their mileage inside 128.
-- Routes that mysteriously stop at expressways. MA 135, MA 109, MA 37, MA 4/225, MA 228. Bring them to some logical conclusion on the inner end.