Regarding the parking/biking tradeoff on Walnut St., some have asked: why not both? Put on your traffic engineer hat. What would you do to accommodate bicycles on streets with legal, but light parking and insufficiently wide right-of-way to have both parking (you need 7′ or so) and bike lanes (you need 5′ or so) in addition to motor vehicle travel lanes (10 or 11′ each)?
There are significant portions of Newton’s major arteries where the road isn’t wide enough for bike lanes and parking, but there isn’t much actual conflict between parked cars and bicyclists outside of the travel lanes. For the most part, riders comfortable and willing to ride on the road without explicit bike accommodations can fairly safely dip into the travel lane to go around the occasional parked car*.
The problem is that Newton bicycle use won’t grow enough if it’s limited to those who are comfortable riding on roads that do not have explicit bike accommodations. And, regulations and guidelines preclude the city striping bike lanes where parking is allowed.
So, in a road with less than 44′ of right-of-way, how do you accommodate bikes and allow occasional parking? Putting bikes on alternative routes is not a valid answer for this exercise.
Note: proposing sharrows will get you no more than a C-. Sharrows in the travel lane are sub-optimal, because they suggest that bicyclists ride in the travel lane when there is lots of (safer) room on the shoulder. Sharrows in the shoulder are out, because you can’t suggest that cars park where bicyclists are explicitly encouraged to ride.
* This is not necessarily an opinion shared by the broader bicycle advocacy community.