Seattle Times Editorial Board Flunks Geometry

The Seattle Times wants your neighborhood arterial to look like this. Photo by Bruce Englehardt.

In recent years, the Seattle Times has published many editorials and columns skeptical of transit, or any transportation mode except private cars. STB hasn't usually responded, because events have shown amply that every day the Times gets more out of step with citizens' increasing desire for alternatives to sitting in traffic. And the Times gets credit for consistently excellent news coverage of transportation topics, led by ace reporter Mike Lindblom.

But the Times's latest ($) finally warrants a response, because it distills so many myths and bad ideas about transportation into a few words. The idea is not to get into a fight with our local paper, but to explain why transit investment is the only way to free people from congestion. The Times's core request - to provide so much capacity for car traffic that a complete closure of I-5 would have little effect on car travel times - is geometrically impossible. Worse, any attempt to make it happen would cause profoundly destructive consequences for the city and its residents. And the reasons (below the jump) show exactly why support for transit, not more car capacity, is the best way forward from our congestion woes.

City Transportation Is About Using Space Efficiently

Everything below stems from one problem: in a developed city like Seattle, the amount of space allocated to transportation is basically fixed. Roads are not getting wider. Making city roads wider requires condemning and destroying all existing buildings next to them, which is mind-bogglingly expensive and destructive. The only other ways to add space for transportation are to dig tunnels, double-deck roadways, or build elevated structures, all of which are also expensive and difficult. We can only afford a small number of new rights-of-way, at most.

So most efforts to improve city transportation are about using the fixed amount of space more efficiently. That involves more than just packing more people in. But geometric reality is that cars start out at a huge space-efficiency disadvantage. This chart shows why.

Includes typical space between vehicles in heavy traffic. Transit vehicles at comfortable load, not maximum crush load.

The upshot is that it's not possible to increase capacity significantly by putting more cars on existing roads. They just take up too much space ($). SDOT and WSDOT have been trying to squeeze in a few more cars for years, using a basket of strategies from ramp meters to traffic signal optimization to "intelligent streets." But these improvements have always been around the edges. The Times's favored "improvement," removing bike lanes, would be no different. Doing so would barely add any capacity, let alone enough to handle an I-5 closure without disruption. This is borne out by city statistics that show minimal change to peak vehicle throughput and travel times from project after project where bike lanes were added.

There is zero evidence that bike lanes or rechannelizations have made the street network "less resilient and capable of handling surges," as the Times alleges without support, or that undoing them would help. In fact, a scan through the Times's own archives shows that I-5 accidents just like last week's have been snarling Seattle's surface street network for many years, since well before anyone thought of a bike lane.

There Will Always Be Traffic Congestion

Another result of how much space cars occupy is that it doesn't take many cars to create congestion. Just a few dozen cars can fill up multiple blocks and create a traffic jam. In a crowded urban environment, those few dozen cars will show up everywhere, as car drivers exploit any route that is less congested. Every healthy city of any size, worldwide, has serious car congestion. And it's there to stay; the only proven way to eliminate traffic congestion is to undergo economic depression. (Even congestion pricing, long economists' gold standard, is failing in booming London ($) and on our own SR 520.)

Despite some politicians' regrettable promises, even the best transit doesn't reduce traffic congestion. Sound Transit was forthright about this in the ST3 campaign, saying instead that ST3 provides alternatives to congestion. Proving the point are New York's horrible traffic jams, which coexist with the nation's best subway. But expanded car capacity (even where there's room) doesn't reduce congestion either. Demand takes up the slack within a few years no matter how big the roads get. Houston's I-10, 23 to 29 lanes wide, is the single road in the United States with the largest car capacity. It's a monster, 5 city blocks across, that visually dominates every place near it. It's pretty much impossible to cross unless you're in a car. To put it through Seattle, we'd level much of downtown and First Hill. But within half a decade of its most recent expansion, I-10 was suffering just as much congestion as ever.

Ultimately, experience around the world shows that people are willing to put up with a specific amount of car congestion, and will just drive more until congestion reaches that threshold of pain. "Congestion relief" means finding ways around the traffic jams, not making them disappear. Making traffic jams disappear is impossible without economic collapse.

Expanding Roads Has Real Consequences

The Times assumes, without a second thought, that the most important (if not only) purpose of roads in the city is to move cars, presumably to faraway suburbs. But city streets are far more than car pathways. They are the connective tissue of our urban environment. City streets don't just host drivers, who move on after a few seconds. They host many residents and business employees, who spend years on a particular block. They can be attractive destinations or windswept wastelands. They can make for an inviting setting where people throng, like Pike Place, or a horrible environment people go blocks out of their way to avoid, like parts of Aurora Avenue. The people and businesses that call a city street home deserve at least as much consideration as those driving along it. The purpose of the city is to be a city, a destination for residents and visitors, not a car conduit for people going elsewhere.

And most of the steps that increase car capacity make city streets worse for residents and businesses, hurting the city as a city. Adding general-purpose lanes increases driver speed (often without increasing actual car throughput), endangers cyclists, and makes crossing streets on foot far harder. Widening streets makes them into less inviting environments for residents and shoppers; at five lanes wide, even crossing in a marked crosswalk becomes scary. Grade-separating intersections creates canyons that are impassable on foot. The most inviting destinations, the places where people converge naturally, are along narrow, intimate streets with slow car speeds and safe walking spaces. Making streets worse for the people who actually spend time along them - the residents and workers - is unfair, especially when the purpose is not to handle crushing daily volume but (as the Times wishes) to eliminate any inconvenience from infrequent and unpredictable emergencies.

Increased Capacity and Resilience Come from Trains and Buses

If we can't put more cars through our existing roads, and we can't build wider roads without great expense and destruction, then increased capacity has to come from elsewhere: walking, biking, or transit. And we need it; without increased capacity, job growth is strangled. With Seattle's large footprint, walking and biking by themselves can serve only a minority of commuters. Transit has to shoulder most of the load. And it has been doing so, with 95 percent of added commute demand to the city center over the last few years handled by transit.

Half a train load of people on I-5, the day of the tanker crash. Photo by Lee Rosenberg, used with permission.

Fortunately, it's a lot easier to expand transit capacity - either rail or bus - than car capacity. Despite the Times's mockery, Sound Transit's claim that Link has the capacity of 14 freeway lanes is accurate. A single three-car Link train carrying a full, not crushed, load contains twice the number of people depicted in the entire I-5 jam at left (assuming the usual average of 1.2 persons/car). And right now, Link has two- and three-car trains running just every six to 10 minutes. Link will eventually expand to four-car trains running every three minutes, for more than three times the current capacity. It could add even more trains with some signal improvements. And even that's not all: Sound Transit is going to build another, separate north-south Link tunnel with similar capacity through downtown as part of ST3.

Buses can do almost the same thing, with political will. The Times notes correctly that many buses were stuck in traffic last Monday, but ignores why those buses were stuck. Dedicated transit lanes mostly don't exist, and were unenforced where they do. Third Avenue was a wall of stopped cars as far as the eye could see - even during peak hour, when the cars were ignoring restrictions. Without cars on Third, most of Seattle's central bus routes would have run much closer to normal. Meanwhile, buses on Howell Street were stuck in a bus lane that ends abruptly at Yale Avenue, where they must rejoin car traffic. These are not the sort of transit facilities that enable buses to be an alternative to congestion.

But dedicated bus lanes that actually cover entire routes, or at least entire congested areas, can do so. Just like a rail line, a dedicated bus lane is capable of carrying many more people than a car lane. A typical car lane can carry about 1000 persons per hour under ideal conditions, and far fewer in heavy traffic. A bus lane with an articulated bus every two minutes can carry 2000 persons per hour, reliably, with comfortable loads. By far the biggest boost to the capacity of an existing bus corridor is a continuous, dedicated, enforced bus lane. Adding car capacity just puts buses into the same unavoidable car congestion described above, and moves far fewer people. The Times's implication that we would make bus routes more resilient by adding car capacity could not be more wrong; the buses would be stuck in the same jam, just with more cars around them.

Another reason that transit is more resilient than car capacity is that trains and buses alike can take crush loads - something a freeway can't do with cars for obvious safety reasons. Last Monday, Link was much more crowded than normal, but ran almost normally. It absorbed crush loads, in some cases twice normal capacity, with only minor delay.

During last week's mess, Link was the one part of the system that was truly resilient, which makes the Times's casual dismissal of Link in favor of feverish car capacity dreams baffling. Link is not "an option for most people" only because it hasn't yet reached most places. After ST3's Link network is built and King County Metro reorients the bus network around it, 73 percent of King County residents are expected to be within walking distance of either Link or a connecting bus running at least every 15 minutes all day. For most trips involving the center city, Link will be an option, and it will be the one that handles emergencies, bad weather, and routine growth best. The Times should recognize transit's critical role in allowing our regional good fortune to continue, not denigrate it to serve a geometrically impossible vision of car growth.