A lot of people had awful commutes last night, thanks to snow. And a lot of people had fine ones. One explanation for the difference: Suburban roads are far more susceptible to catastrophic breakdown than urban street grids.

Traffic congestion on snow night. Image from Google.

Snow storms like last night’s highlight how easy it is to completely shut down suburban-style transportation systems. And conversely, how comparatively resilient are more urban systems.

Cities beat suburban areas on snow resiliency in two big ways: Multimodalism and network connectivity.

First and foremost, with transit, walking, and biking more convenient options, cities are simply much less reliant on having clear roads. Metrorail worked like a dream yesterday, and pedestrians had a lovely commute.

It simply didn’t matter how bad the roads got for a significant percentage of DC’s travelers, because they simply weren’t on the roads while they traveled.

Don’t put all your eggs in one basket

But that’s not all. Even for car drivers, urban street grids are more resilient than road systems focused around large highways, because of how they’re laid out.

The great thing about interconnected grids is that if one street becomes blocked, there’s another perfectly good street one block over. And another one block down.

If a wrecked car or fallen tree or whatever blocks the street you’re on, you just take a different street. There might be some additional turns involved; it might not be quite as direct. But for the most part 28th Street isn’t all the different from 29th Street.

Contrast that with suburban-style systems where all traffic in a particular area funnels onto one big highway. If that one highway becomes impassible, everyone in the area is stuck. Or, at best, they have to drive miles out of their way to find the next big highway.

This illustration shows how that works. If the “Collector Road” gets jammed, people in the top half of the image can still move around. People on the bottom half can’t.

Suburban-style roads vs urban street grid. Image from USDOT.

That’s part of what happened last night. There were a lot of crashes. If they happened on arterial highways with no parallel roads, which a lot of them did, that road would succumb to gridlock.

Urban places aren’t immune, but they’re better off

To be sure, this storm was bad for roads all over the region.

Streets in Northwest DC were just as dangerous as those elsewhere, and DC’s plowing response was bad. And buses were every bit as stuck in it as cars.

But there’s no doubt that people who could travel via Metro or foot had a much better time, and there’s no doubt that drivers who could use parallel streets were able to bypass some of the congestion on arterials.

 Comment on this at the version cross-posted to Greater Greater Washington.
 
 
 

What do you do if you have active freight rail tracks running down the middle of a downtown street? Add bike lanes, of course!

East Avenue, Clearwater, FL.

This is East Avenue in downtown Clearwater, Florida. It’s one of America’s most unusually multimodal streets.

On the left: A normal one-way general purpose lane with normal car traffic. In the middle: Freight rail tracks. On the right: A major regional two-way bikeway, the Pinellas Trail. What could go wrong?

Actually, it’s not as dangerous as it looks. Freight traffic on those tracks is relatively light, and extremely slow-moving. The train in this photo was moving maybe five miles per hour. And unlike cars, trains don’t suddenly change lanes. There’s zero danger of a CSX right hook.

In fact, the rail tracks are effectively a buffer between the bikeway and car lane. They make a bigger buffer than normal buffered bike lanes get. In a weird way, the tracks are a sort of protection.

So it’s totally bonkers. But maybe it works.

What do you think?

 Comment on this at the version cross-posted to Greater Greater Washington.
 
 
 

According to the California housing champion who’s suing communities that don’t allow enough new development, not building needed density is morally equivalent to tearing down people’s houses.

Photo by .Martin. on Flickr.

Sonja Trauss, founder of the SF Bay Area Renters’ Federation sums up the housing problem affecting nearly every growing American city today:

“Most people would be very uncomfortable tearing down 315 houses. But they don’t have a similar objection to never building them in the first place, even though I feel they’re morally equivalent. Those people show up anyway. They get born anyway. They get a job in the area anyway. What do they do? They live in an overcrowded situation, they pay too much rent, they have a commute that’s too long. Or maybe they outbid someone else, and someone else is displaced.”

Trauss hits the key points: The population is growing, and people have to live somewhere. If we refuse to allow them a place to live, that’s just like tearing down someone’s home.

Someone else is displaced

Trauss’ last sentence is particularly important. It explains how the victims of inadequate housing often are not even part of the discussion. She says “Or maybe [home buyers] outbid someone else, and someone else is displaced.”

Here’s how that works: One common argument among anti-development activists is that new development only benefits the wealthy people who can afford new homes. That’s wrong. It’s never the wealthy who are squeezed out by a lack of housing. Affluent people have options; they simply spend their money on the next best thing. Whenever there’s not enough of anything to meet demand, it’s the bottom of the market that ultimately loses out.

Stopping or reducing the density of any individual development doesn’t stop displacement or gentrification. It merely moves it, forcing some other person to live with its consequences.

Every time anti-development activists in Dupont or Georgetown or Capitol Hill reduce the density of a construction project, they take away a less-affluent person’s home East of the River, or in Maryland, or somewhere else. The wealthy person who would have lived in Capitol Hill instead moves to Kingman Park, the middle class person who would have lived in that Kingman Park home instead moves to Carver Langston, and the long-time renter in Carver Langston gets screwed.

As long as the population is growing, the only ultimate region-wide solution is to enact laws that allow enough development to accommodate demand.

 Comment on this at the version cross-posted to Greater Greater Washington.