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Look, this "3% of trips" argument is tired.

Let me break it down: What percentage of trips in the region take place on I-90? Is it any more than 3%? I doubt it.

Let's say we have 10 million trips per day in the region (reasonable; the PSRC says we'll have 20 million per day in 2040 with less than double the population). There are about 160,000 trips per day on I-90. That means I-90 accounts for 1.6% of trips in the region, daily.

With ST2, we're looking at an increase in daily trips in the region of about 1.5% - from 3% to 4.5%. Let's split that between the light rail corridors - most of it will be in the north and east corridors, so let's say .4 of that 1.5% will end up in the east corridor. That's a big number! With 1.6% of trips in the region over that bridge, a full quarter of them would be on light rail?

Now, doesn't that make the 3% argument seem silly? You wouldn't argue against replacing I-90 when it needs replacement, but it only carries about 1.6% of trips! Look at how much it would cost to build a new I-90 without all that existing ROW, and then tell me with a straight face that these new rail transit corridors aren't cost effective.

Posted by: Ben Schiendelman | May 16, 2007 11:04 PM

One more thing: The claim that the express lanes carry a third of I-90 traffic is not only wrong, it's basically impossible: There are three travel lanes each way in the general purpose roadways, and only two limited access express lanes. You're actually looking at less than a quarter of the theoretical capacity, and a lot less than a quarter of the actual trips carried.

In actuality, projected ridership on that corridor in ST2 (using federally approved models) is much greater than current use of that roadway. In addition, trips in that corridor during rush hour will take less time than vehicle trips, making them more time-efficient.

90's GP lanes are at capacity, and we're growing.

Posted by: Ben Schiendelman | May 17, 2007 11:36 AM

This comment is in response to Ben Schiendelman's two comments above.

In his first comment, by using imaginative arithmetic with hypothetical numbers and dubious assumptions, Ben comes up with the bottom line forecast that 25% of person trips in 2030 that use I-90 for a portion of the journey would be on light rail.

Rather than dissect his work, let me jump immediately to the Sound Transit forecast for I-90 light rail of 44,000 per day in 2030, combined with Ben's I-90 cross-Lake vehicle forecast of 160,000 per day, and a recent U of W measurement of average vehicle occupancy on I-90 cross-Lake of 1.4 because of many car pools and buses. 1.4 people in 160,000 vehicles is 224,000 people. Adding 44,000 people in trains makes 268,000 total people crossing the bridge daily in road vehicles and trains. 44 thousand divided by 268 thousand equals 16% in trains, not 25%.

This forecast is based on extrapolations of present-day technology, without taking into account changes in automobile and railroad technology that may increase the attractiveness of one relative to the other.

Ben and I probably agree that moving as many people as possible in mass transit is a good thing. But as a Sound Transit fan, Ben wants massive transit, including four-car trains longer than a football field moving through urban and suburban neighborhoods, instead of clean, quiet, flexible mass transit that uses the road infrastructure we already have in place.

And consider why building passenger railroad tracks on the I-90 floating bridge is not a cost effective use of that existing infrastructure. The reason lies in how to achieve the most high-capacity use of the two bridge lanes that the proposed light rail train tracks would occupy on what is now the reversible HOV expressway that occupies the I-90 Center Roadway.

Sound Transit's light rail trains will have five minutes minimum spacing between them, because of the system design that has the westbound trains from Bellevue merging with the northbound trains from Sea-Tac Airport to create a single combined stream of trains at 2.5 minutes spacing heading north through the former downtown Seattle bus tunnel and then into the proposed six-mile, three billion dollar subway tunnel that goes to Capitol Hill, U of W, and Northgate. Five minutes of spacing between trains at 60 miles per hour (one mile per minute) amounts to five miles of empty track space between trains.

The high capacity transit alternative never seriously considered by Sound Transit is to continue using the Center Roadway for buses and other HOVs, which because they can be much more closely spaced than trains can provide much more people moving capacity.

It's a myth, an urban legend, that light rail trains offer higher capacity than buses.

Buses that use the Center Roadway, unlike trains, can be routed all over the Eastside to serve many communities with one seat rides, as opposed to operating a two-mode system where feeder buses take people from neighborhoods to a string of train stations along a single rail line. With traffic lights that give buses priority by extending the green or truncating the red, with some HOV lanes on arterials, plus other Bus Rapid Transit technology such as pre-payment of fares to load faster, a bus network provides a comprehensive network of geographically extensive service that carries the same or even more people for billions less than the cost of a single passenger railroad.

Finally, Ben did not factor in existing traffic flow modeling in his challenge of the claim in the Kargianis-Talmadge op-ed that with light rail "the I-90 bridge would suffer a vehicle capacity loss of one-third compared with today." Vehicle capacity on the I-90 bridge is not linearly proportional to the number of lanes under conditions of heavy use that leads to traffic congestion, beep and creep slow movement, and loss of smooth flow.

While I don't know exactly which study is the basis of the 1/3 capacity loss claim, I do know that computer-based traffic modeling carried out by WSDOT and others indicates that the scale of reduction noted by the op-ed authors is entirely within the realm of possibility on some segments of the cross-Lake corridor if the Sound Transit railroad is built.

This is true even though WSDOT would restripe the three general purpose lanes in each direction of the I-90 outer roadway into four narrower lanes, one of which would be HOV, supposedly replacing the Center Roadway HOV lanes. Problem is, narrower lanes mean slower speeds and more accidents.

Bottom line -- losing that I-90 Center Roadway to trains that will operate with miles of empty track between them means a reduction of people-moving and freight-moving capacity cross-Lake. This is an especially critical objection for the various industries that move 4,500 trucks per day over that bridge.

(Ed. - John Niles is a Senior Fellow at Cascadia Center For Regional Development).

Posted by: John Niles | May 18, 2007 2:54 AM

Hi John,

I stand at the I-90/Rainier freeway stop watching traffic go by during rush hour most mornings. I'm sorry if this is anecdotal, but when I see cars going by in the express lanes every 2-3 minutes - while the GP portion of the freeway sees more like 2-3 cars per second - I can't take seriously Talmadge or your contentions that losing these would reduce capacity by 1/3. Even if it did reduce theoretial capacity by 1/3, those express lanes don't carry anywhere near their capacity, nor can they because of the single-lane feeders that serve them. When the GP lanes are completely backed up and the express lanes are wide open, it should be clear that the GP lanes are carrying 90%+.

When you talk about all this capacity in the HOV lanes for buses rather than rail, you seem to be ignoring the major differences: rail across the bridge would eliminate transfers for those coming from the heaviest in-Seattle transit corridor (Downtown to Northgate); rail would have zero traffic lights in that corridor; rail would not be affected by traffic congestion. The HOV lanes themselves are generally moving at full speed - but the roads feeding them are affected by the same traffic everyone else is in - and buses would be stuck in that traffic as well.

John, I can see coming through exactly the concern you spoke to me about: You lost your one-seat ride in DC to a transfer between a bus and a train. But even if you didn't see it then, you can see now that many more people ride that train than ever rode the bus - and you can see how congested the roads would be if all those people in DC were on the surface. Here in Seattle, we don't have a way to increase roadway capacity over I-90, and we need to move more people. We already run full buses over the express lanes, and just redistributing those buses won't get people out of their cars. We actually need new capacity.

I'm trying to figure out what your real opposition to rail transit. When you're the only one claiming rail will reduce capacity over I-90, it seems like you might do well to consider why all these other people disagree with you. We're creating new corridors in Seattle and on the eastside and, as part of building all this new capacity, changing the use of the express lanes from cars to transit.

So, do you have a 2030 scenario where 44,000 people use those express lanes every day without them being rail? Could it be implemented now that Bellevue, Kirkland, Issaquah and Redmond have all expressed to Sound Transit their preference for rail in that corridor instead of buses? It seems to me that fighting the current choices here won't solve anything.

Posted by: Ben Schiendelman | May 19, 2007 10:36 AM

Ben:

Opposition by members of several organizations to constructing new passenger railroad tracks in the greater Seattle region is founded on the concept of productivity:

For each $100 million dollars of public investment, what design of public transit system will attract and serve the most people?

The contemplated 125 mile light rail network from Sound Transit has been a loser in this regard since the beginning of the technical studies in the early 1990s.

A complete dissection and autopsy of the 1993 system level study, the [i]Regional Transit System Plan Final EIS[/i], has been completed by Dr. Richard Harkness and posted here.

A key explanatory point made by Harkness:

"A fundamental problem with the 1993 FEIS is that it compared alternatives that differed in both cost and benefit. In theory this can be dealt with by careful focus on cost-effectiveness, but RTA [earlier name for Sound Transit] botched the job. Essentially, RTA concluded that an $11.5 billion rail alternative would perform better than a $4.7 billion bus alternative. This was simple-minded, and is essentially like comparing proposals to build a brick wall costing $20,000 with a concrete wall costing $10,000; then deciding bricks are a better technology since the $20,000 wall would be higher than the $10,000 wall."

On the official claim that passenger railroad capacity on the I-90 Center Roadway is higher than using the express lanes for buses, vanpools, and shared-ride automobiles, I already explained that buses can be spaced more closely than trains.

I invite your attention to the diagrams here, prepared by transportation engineers Jim MacIsaac and Bill Eager. The first picture in that chapter of a longer presentation shows that the express bus equivalent to Sound Transit's 12 trains per hour is 60 buses per hour.

If those buses used the Center Roadway, approximately 25 smaller HOVs (shared-ride cars and vans) could fit between each bus. Or, if you like, use more buses and fewer small HOVs. Just 120 buses per hour would provide double the passenger capacity that ST can get out of its four-car light rail train design where Eastside trains merge with South King county trains.

Routing buses in any number of ways to and from the Eastside could and would provide more service than a single light railroad line with a small number of congested stations fed by feeder buses and dropped-off passengers. Does this mean spending some money to give buses more priority over cars on crowded arterials -- yes it does. This is a policy fight that environmentalists should be eager to take up.

The fight for sustainable transportation around Puget Sound has to take place on the existing street grid -- sustainability will not happen by supplementing streets with multi-billion dollar urban train tracks.

The reduction of I-90 truck capacity shown in the second diagram here uses data from the I-90 Center Roadway study prepared by professional consultants DKS for the Washington State Department of Transportation. The study is posted here.

As a counterpoint to the misleading information posted by Sound Transit and the RTID Planning Committee on their joint Web site, and with help from many other people, I am compiling educational information on the $39 billion Roads and Transit package here.

Posted by: John Niles | May 21, 2007 3:46 PM

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