Thursday, March 3, 2016

Criticism of Tunnel Effect at Mirror Pond Site Mistaken; Enclosure is Important

Now that we have a decision for the O'Brien site securely in place, maybe we can do some less-heated post-mortem investigation on the Civic Center discussion.

What about a Tunnel Effect?

One of the things about the now-abandoned Mirror Pond site for a Police Station that occasioned criticism was the prospect of a "tunnel effect" Commercial Street between the proposed Police Station and the South Block apartments.

Abandoned Mirror Pond Civic Center concept from June 2013
I believe this was something of a mistake and that continuing to think with this approach about the way building faces enclose a street or other public space significantly hampers our ability to plan and build useful things elsewhere.
Here is a magnificent "tunnel effect"!

Salem should be so lucky to have something like this!

1:2 and 1:3 building-to-street enclosure ratios
(Institute of Transportation Engineers)
The fairly mainstream Institute of Transportation Engineers says
The threshold when pedestrians first perceive enclosure is a 1:4 ratio of building height to thoroughfare width—typical of low-density environments. In denser urban contexts, height-to-width ratios between 1:3 and 1:2 create an appropriate enclosure on a thoroughfare.
Density and ratio are a relative things here. You'll note that example from Seville has a ratio closer to 1:1 or maybe even 2:1 than to 1:2 or 1:3.

It speaks to Speck's point about the dinner party. Looking at pre-auto and European examples, contemporary urbanists often argue ratios larger than 1:1 are appropriate, lively, and pleasant.

A Civic Center Site was an Opportunity, but not Best Tunnel

The Civic Center concept had some advantages, but at the same time it wasn't easy to rally behind with any enthusiasm.

First, it is clear that Commercial Street at the Civic Center is not nearly so civilized as the street in Seville. So that obviously isn't something we could have duplicated there. (So it's not like criticism about a tunnel there is 100% wrong. The lack of sidewalk-scaled interest along the parking garage at South Block seriously detracts from the possibilities for a stimulating street and building enclosure here. Pairing that with a Police Station doesn't inherently point to a lively, walkable sense of enclosure.)

But it also seems like Peace Plaza is a bad, even broken, public space. The plaza between the Library and City Hall is another "tunnel" and suffers from blank walls, poor connectivity on the edges, and insufficient other adjacency to provide additional activity. It's a dead space most of the time.

A new Police Station and set of seismic updates was an opportunity to reconfigure the Civic Center. The proposed building you see at top doesn't do that, and that proposal for a new Police Station at the Civic Center didn't grapple deeply enough with rethinking the way the Civic Center works. There might have been an opportunity for a new vision at the Civic Center that could have commanded more enthusiasm and support.

The O'Brien collection is bigger than you think
(SCI student study from five years ago.
Notes added)
The O'Brien parcel has its own opportunity costs, but it's also true that the O'Brien parcel has been for sale for a while, and no one was rushing in there to redevelop it as apartments. The loss of the O'Brien parcel for potential housing is significant, but I don't see it as catastrophic. It's a trade-off, and a defensible one. (Provided we keep talking about the need for downtown housing.) Crucially, there are other parcels that can still be redeveloped. On the south part of the greater four-block ensemble are three half-lot units nearer to Union Street. That makes walkable/bikeable redevelopment easier! If housing on those sites remains in play, the whole thing seems like an ok set of trade-offs. Not optimal, but alright.

I don't want to go back and re-litigate the proposal for a Police Station at the Civic Center. I think that claims it was best are overblown and claims it was worst were overblown. Not using that existing land at the Civic Center is a renunciation, it's true, and there are very real opportunity costs about the O'Brien site. But the renunciation is not a grave one. We'll manage just fine with the O'Brien site.

Mid-Rise and Enclosure

Instead, the I want to suggest we think more about the way we used a "tunnel effect" to argue against the Civic Center. As we'll have similar arguments in the future, "tunnel effects" ought to be something we think more about in a critical way.

An allergy to mid-rise forms and an embrace of low enclosure ratios goes hand-in-hand with excessive autoism. If we want supremely walkable places, we need to be open to some higher forms of mid-rise.

Pioneer Trust Bank: Mid-rise perfectly scaled here
And it's not like Salem doesn't have good examples. The Pioneer Trust building is just down the street. Waterplace is a block away. The Franklin/Masonic building is a couple more blocks. The Montgomery Ward/Skiff building. All these fit very nicely with our wide downtown streets and do not dominate them.

Only one building might actually dominate. The great exception in height, the Livesley building, sticks out, and Salem doesn't need any more towers like that.

Going down in scale, most of our two-story downtown is too small for our 99-foot street widths, in fact. This contributes at least a little to the zoominess of downtown traffic.
Here is it easy to see how this notion of "enclosure" also scales for residential streets and calms traffic. The principle for downtown is the same. Narrowing the perceived width of streets is a sound move for better walking and biking.

We sure could use a greater number of modest mid-rise buildings, and we should embrace well-designed corridors that offer the aesthetic experience of enclosure.

Over-simple arguments against "tunnel effects" will doom our efforts for more walkable spaces and buildings.

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