Sunday, August 20, 2017

Eclipse and Carmageddon Chance to Think Critically about Capacity

Maybe the gridlock will materialize, maybe not.

However it shakes out, the prospect of the eclipse of our current auto capacity today or on Monday is going to be a great time to think about the geometric limits of auto capacity.

Simply put: Cars are space hogs.

ODOT knows:
Cars use space and funding inefficiently!
At some level ODOT knows this. This graphic is from a 2014 planning process. (The final plan is here; this graphic is on p.50.)

But at the level of budgets and funding, they are in deep, deep denial. (City Observatory has some recent analysis of this: "What a congestion report doesn’t tell us about congestion," "Dying to widen highways," and "Why we’re talking about Portland’s freeway widening proposal."

Cars in motion take more space than we think.

One way cars consume space
Cars at rest also hog space.

Downtown Surface Parking Lots in Red
Parking Garages in Solid Brick Red
On-street parking stalls not included
(click to enlarge)
You might remember this graphic from a few years back. We have hollowed out a tremendous amount of downtown for surface parking and structured parking. It's like swiss cheese! We have amazing amounts of land devoted to temporary car storage.

SE Corner of Chemeketa and Commercial, then and now
Then: Eldridge Block circa 1940, Salem Library
Inset, today: Chemeketa Parkade
(Click to enlarge, more examples here)
Whether they are moving or are at rest, cars have a voracious appetite for space, and we have allowed them to consume a disproportionate amount of it.

Space hogs: Drive-alone trips vs one big bus
(See the great twitter thread by Brent Toderian, credit unknown)

Capacity and through-put
(from Terra Nova, by Eric Sanderson,
via "Forget the Damned Motor Car")
Postscript, August 24th

Only after the Eclipse on Monday was there a problem with gridlock, and it was mostly on the highway. From ODOT, here's the average traffic speed charted on two segments of I-5, with the Eclipse-related slowdown very clear:

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