The answer in the Beltline is super blocks, isn't it? Identify the car-centric roads and make the others better for walking/cycling.
I don't really think so.
First, for the unaware: a superblock is a semi-pedestrianization policy from Barcelona. The figure below shows roughly the scheme:
This is the best diagram I can find, but essentially the outer roads around a 3x3 grid of blocks remain more or less untouched, while the internal ones are only used for access, so the U shaped "pedestrians and vehicles" space functions as access to the buildings, but you can only make right turns on them, so you come in off the main road, and then drive around the block (accessing whatever building you need) and back out to the main road.
This then frees up more space to be used for parklets and the like, and permits pedestrians and cyclists to take direct short routes, while forcing cars onto the main roads. For instance:
Before After
The two reasons I don't know if it's the right solution for the Beltline are:
1). Barcelona intersections are huge, chamfered things, so closing them gets you real space. They're on the order of 20,000 sq ft, where a standard minor intersection in the Beltline is more like 4000 sq ft. So you don't get nearly as much space to do cool things with. (The street widths are similar, although Barcelona has more pedestrian space by having no setbacks for the buildings, but wider sidewalks instead.)
2). If you did it here, presumably the streets that would not get closed to cars would be every third street - Macleod (2nd St E), 1st W, 5th, 8th, 11th, 14th. But those are the streets that we actually need the pedestrian space on! For one, they are the ones with commercial activity, and for another, they are the ones that provide access to the downtown. (Since they are the ones with downtown connectivity, it would be hard to close them to cars.)
In a peverse way, I almost wonder if a more workable variant would be to implement a superblock type fixture on the side streets, but use it for angle parking, then taking parking space and lanes on the through streets for more pedestrian and cyclist space.
www.beltlineyyc.ca
