I wanted to give my perspective on the design difference between the DC streetcar and a potential for design on Sandy/Broadway. I am a little worried Portland will make the same mistakes.
In DC the streetcar was added to a 4 lane road + parking (H Street NE) without dedicated lanes. Here:
https://www.google.com/maps/place/Wa...=en&authuser=0. It also precluded any bicycle facilities much like when NW Lovejoy had considerations for further bike lanes halted when the streetcar was put in. This is a heavily cycled area of town.
Sandy is a very similar space to H Street NE prior to the massive infrastructure investments that have taken place in the last decade. Both are car-centric designs with a potential for large numbers of cyclists. Because it is a heavily traveled bus and streetcar route, as well as a restaurant destination, H st consistently looks like one of those traffic games where no one can move. Sightlines for pedestrians are often attenuated, making crossing hazardous as cars often pass and run reds in the center lanes.
I would support a streetcar on Sandy only if it were a median separated design with its own ROW (similar to Interstate). During peak hours Interstate is fairly safe because 1) signtlines are not blocked adjacent to the sidewalk 2) one lane of traffic regulates the max speed 3) pedestrians crossing distance is much shorter. Otherwise, its addition would likely make the street less safe for pedestrians, and make it mostly useless as a means of transportation as the design in DC has become.