Greater Greater Washington


Gaithersbungle, part 7: 30% mode share is totally unrealistic

The Gaithersburg West "Science City" Master Plan hangs its "Smart Growth" claims on the Corridor Cities Transitway, a proposed transit line from Shady Grove northward to Gaithersburg and Germantown. The plan insists that 30% of commuters will ride the line. That's highly dubious. You can design a circuitous, low-quality transit line and claim many people will ride it, but that doesn't make it so.

To satisfy the political pressure of enabling development on every parcel, the Planning Department proposes rerouting the line from an already-circuitous route (red) to an even more circuitous one (blue). This reroute took the line away from the DANAC property, whose owners originally developed it with the promise that they would have a CCT stop. The published draft of the Master Plan, however, eschews any new development on DANAC's property. After the owner complained and put pressure on the board, they added a stop back in.

Corridor Cities Transitway alignments. Left: Entire alignment before latest rerouting. Right: Proposed reroute not including DANAC station.

The Planning Department also recommended BRT over light rail, claiming it would actually draw more passengers because buses can leave the transitway to circulate through nearby neighborhoods. Rerouting the line through more of the office parks in Gaithersburg West also added riders under the Planning Department's model. Without seeing the underlying models, there's no way to know how they arrived at this result or whether it's correct, but it sounds like the model assumes that more frequent stops on a more circuitous route that passes closer to people's homes will draw more riders than a faster route that connects major, dense centers.

The plan claims that Gaithersburg West will achieve a 30% mode share between the density, transit, and Travel Demand Management (TDM) programs. According to a Fairfax County presentation on Tysons Corner, the Rosslyn-Ballston corridor's mode share is 26%, Bethesda's 19%, and downtown DC's 51%. Achieving 30% in this distant, auto-dependent area with buses following a long and winding route seems highly dubious.

According to the Action Committee for Transit, planners arrived at 30% by assuming that the mode share will match White Flint. However, White Flint is right atop a Metrorail station, closer to the region's core, and very close to many more jobs. It also assumes that 24% of people will carpool, while the current actual number is approximately 5%, and carpooling has declined regionwide in recent decades. According to ACT, COG's modeling of this area predicted that 8% of people will actually take transit to work absent residential development, and there is far too little residential development to boost the number anywhere near 30%.

Nor does the plan enforce that 30%. The staging requirements do mandate that most of the development can't happen until the CCT is at least funded and under construction, but that's no guarantee anyone will use it. If the County wanted to truly enforce the 30%, they could allow the development only if mode splits are really meeting the projections, or impose impact fees on the new development if they don't.

Critics have charged that JHU isn't really serious about building a research campus at all, but that they rather want to make a lot of money on turning their farm into an office park to fund their main operations in Baltimore. We don't know for sure if that's the case. But if it is, and the 30% mode share and everything else are just a smoke screen, the County Council should put some teeth into the 30% requirement, enough that building an office park without that kind of mode share ceases to be a cash cow for JHU.

A county could develop a bus system that stops at 20 people's individual houses, drives for 30 minutes, then drops them off one by one at their jobs, and call it BRT. They could then spend billions to make a very wide expressway and lots of interchanges to speed drivers. And finally, they could write a plan that claims that one-third of the people will ride this transit system. But we would laugh. And that should be our reaction to this plan as well.


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David Alpert is the founder of Greater Greater Washington and its board president. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He now lives with his wife and daughter in Dupont Circle. 


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This keeps getting worse by the hour. How much has been spent on these "studies" so far? They seem to exist soley to justify a foregone conclusion.

by monkeyrotica on Jul 31, 2009 12:17 pm • linkreport

The silver lining to the Corridor Cities Transitway being pushed for BRT is that when its terrible design fails, nobody will blame light rail.

by BeyondDC on Jul 31, 2009 12:40 pm • linkreport

That's a rather pyrrhic victory, BDC? Besides won't they just blame mass transit and keep on hoping for their fuel cells?

by цarьchitect on Jul 31, 2009 3:03 pm • linkreport

You are onto something, monkeyrotica. That's why the Action Committee for Transit and Greater Greater Washington have been taking positions against this whole Gaithersburg West Plan as it currently exists.

It looks just like Olney back in the 1970's and 1980's: build a bunch of car-dependent sprawl, call it "transit-oriented," and then don't build the transit. It's a bad idea and runs counter to the Smart Growth policies of the county and the state.

by Cavan on Jul 31, 2009 3:52 pm • linkreport

That was tongue in cheek. Mostly.

by BeyondDC on Jul 31, 2009 5:03 pm • linkreport

eh, just let the developers have their way.
I doubt that the areas surrounding the stations will be up zoned for higher residential in any case.
In fact, I bet most single family homes in the areas are prohibited by HOAs from renting basements or having separate entrances.

I'm starting to see the value in grid based street designs.

by shy on Jul 31, 2009 8:14 pm • linkreport

I guess I kind of figured. But, the second part of my comment is true. Politicians don't usually get the difference between implementation and concept.

by цarьchitect on Jul 31, 2009 9:24 pm • linkreport

When busses start to circle around neighborhoods doesn't that disqualify them from being termed as BRT?

by Lisse24 on Jul 31, 2009 10:29 pm • linkreport

I'm not buying the 30% number. I find it inconceivable that people who would (1) live in MoCo,(2) work in Science City, and (3) earn the kinds of incomes Science City would support would ride buses to/from Science City at that rate. I'm for CCT, but I just don't find that 30% number believable.

If that is a valid assumption (big "if"), then is there at least a stated intent to reduce parking requirements by 30% in that area if/when Science City is implemented?

Quick notice of possible typo? "... the Planning Department proposes rerouting the line from an already-circuitous route (red) to an even more circuitous one (blue)" The red route looks like the more circuitous one to me (?)

by Ingemar on Jul 31, 2009 11:22 pm • linkreport

The Planning Department also recommended BRT over light rail, claiming it would actually draw more passengers because buses can leave the transitway to circulate through nearby neighborhoods.

This is the model Ottawa (Canada) and Brisbane (Ausralia) use in their very successful rapid transit bus projects, in which buses start local in neighborhoods, and then enter limited stop operation in a grade-seperated corridor with defined stations. (start at page 35/116 for a description of the two cities)

When the buses enter the main transitway, they function as light-rail would. Very frequent service, limited stops, and pre-payment before boarding. They can also go express within the transitway as well. At terminal points on the line, they branch out into neighborhoods.

This can be an inexpensive way to add service to neigborhoods - one of the problems with feeder bus service to rail stations is that you've just imposed an additional time penalty on riders (you have the feeder bus wait time, dwell time, and then travel time, as well as the same for the rail line you'd be waiting on)

It's not a bad model for a suburban jurisdiction with moderate density on a corridor and low density in the neighborhoods. However, like you all, i'm seriously skeptical of a 30% mode share. Seriously? That's what DC and San Francisco have as a percentage of people using transit to get to work.

by AA on Aug 1, 2009 12:20 pm • linkreport

Ingemar, you are absolutely right. quel joke. anyone who can afford a car will use a car, in most situatons. "Science CIty" won't be dense enough to be an exception.
If the development itself is worthwhile, don't hide behind a screen of rapid transit that won't be used.

by faye zincrowd on Aug 1, 2009 2:17 pm • linkreport

David, you have covered most of the absurd issues regarding the Gaithersburg West Master Plan (GWMP) and I applaud you.
One issue that bears more discussion is the fact that many of the people along the route of the CCT live in subdivisions that were designed to be auto-dependent...we need our cars to get out of the subdivisions so if parking is limited at the CCT stations as planned, the CCT is useless. (To see a map of our curly streets and cul-de-sacs, see "The Gaithersburg West Master Plan and the Magic Carpet" on the Civic Groups page of .)
Another issue to consider for those of you who think the CCT is a good idea is that the CCT is the justification for calling "The Science City" a "transit oriented development". This allows much higher density so the County is proposing 20 million square feet of space and 5,700 housing units to bulk up the area to secure the funding for the CCT.
However, the CCT is only expected to carry about 15% of the additional population which leaves 85% of the added people in their cars. This will result in approximately 43,000 more cars in and around the "transit oriented development".
To accommodate these 43,000 extra cars the Planning Board has proposed five multilevel 10- and 12-lane highway interchanges, some of which will be built adjacent to residential neighborhoods. Many of the roads will be widened to six and eight lanes and some will criss-cross the "Science City" dividing it into five separate areas.
The GWMP is designed to provide a cash cow, as David called it, for Johns Hopkins. If you start with the need to put 15,000 people on a 107 acre farm that is directly adjacent to three residential neighborhoods and is not zoned for a high-rise commercial complex, you can follow the trail of absurdities right through the Gaithersburg West Master Plan.

by DB on Aug 1, 2009 5:53 pm • linkreport

Someone mentioned the lack of housing. There are over 25,000 homes within 2.5 miles of the Science City in a full range of prices as well as rentals. The housing proposed in the Master Plan is not included in the staging so there is no assurance that any of the people who live in the 5,700 multifamily housing units will work in the Science City. So much for the live-work-play concept.
Also, speaking of play...some of the recreational features are definitely worth mentioning while we are discussing absurdities. Johns Hopkins Real Estate (JHU) is calling the buffers between the high-rise buildings and the six-lane highways "parks". Muddy Branch Park is supposed to be a 300 ft strip along Muddy Branch Road which will be widened to six lanes and will have, if JHU prevails, the right-of-way for the CCT running through half the length of it. No firm answer has been given as to whether some or all of the 300 ft buffer will be used to widen the road. The Darnestown Park is a 60 ft buffer between the high-rises and Darnestown Rd which is also six lanes. Buffers are good but I think it is stretching it a bit to call the buffers "parks".
In the Science City the "linear parks" are the median strips on Key West Avenue which will be widened to eight lanes. Then there is the "major recreational feature" called the "LSC Loop" which will be a series of roads that will have 20 intersections and will cross a six-lane highway twice and an eight-lane highway twice.

by DB on Aug 1, 2009 8:57 pm • linkreport

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