The traffic legacy of the W&OD railroad, 10/2/2018

Few people other than avid bicyclists know this, but to some degree, the awful traffic on Maple is a legacy of the W&OD railroad.  That railroad cut Vienna in half about a century ago.  And today, Vienna is still very nearly cut in half.  For a roughly 4.5 mile stretch, the W&OD road bed prevented roads from crossing Fairfax County in an East/West direction.  And now, for that entire 4.5 mile stretch, the only  roads that cross the W&OD are a handful of streets in downtown Vienna.  And of those, the only one that can handle any traffic is Maple. Continue reading The traffic legacy of the W&OD railroad, 10/2/2018

Town of Vienna Capital Plan, 9/26/2018

On 9/24/2018, Town council looked at a draft plan for future capital expenditures.  This is the “Town of Vienna CIP Review (Fiscal Years 2019-2034) Presented to Council September 24, 2018″.  I did not attend that meeting, but I can see from the documents that it differs materially from what was in the current budget.  Let me line out the differences that matter vis-a-vis MAC zoning.  The major differences I see are: Continue reading Town of Vienna Capital Plan, 9/26/2018

If Falls Church jumped off a cliff, would Vienna jump off a cliff too? Minor update 9/25/2018

I have been thinking about doing a survey of Falls Church residents, to see how they like their big new mixed-use developments.  In the course of that, my wife brought up the issue of schools, and the fact that Falls Church runs its own schools.  And that question of schools led me to a better understanding of how the incentives for development differ between Falls Church and Vienna. Continue reading If Falls Church jumped off a cliff, would Vienna jump off a cliff too? Minor update 9/25/2018

Visual Preference Survey, 9/22/2018

On this page, I describe what a “visual preference survey” is, why this matters, and why I don’t have much faith that it will result in material changes in MAC zoning.


At the 9/17/2018 Town Council meeting, there was considerable discussion of what needs to be done during the temporary halt in MAC zoning applications.   I list these items in my review of that meeting.  I would have added a few more (e.g., fix the open-space requirement so that it does something), but all-in-all, the entire list of things made a decent work plan for producing MAC buildings that the citizens would not mind living with.

But when the Mayor spoke, she ignored everything but the “visual preference survey” and the resulting “design guidelines”.  In my experience, that means the Mayor probably isn’t planning to do the rest of the items.  Reinforcing that is the  reporting by the strongly pro-developer Sun Gazette,  which mentioned literally none of the other items on that list, other than the “visual preference survey”.  And the fact that the Town had promised to do a traffic study before, and then reneged on that promise.

As I see it, then, there’s a pretty good chance that the only thing the Town is going to do is this “visual preference survey” and the resulting “design guidelines”.  If that’s right, then until such time as our current pro-MAC councilmembers change their minds, this “visual preference survey” is probably the only citizen input to the changes, if any, in MAC zoning. 

So, plausibly, this is all you’ve got.  If you have an interest in MAC zoning, you need to take this survey once the Town makes it available.  Let me now walk through what this is, and what it can and can’t do.


In a visual preference survey, you will be asked to rate pictures of buildings.   From the perspective of the survey respondent, that’s all there is to it.  Typically, you’d rate how much you like each building on a scale from “hate it” to “love it”, or “inappropriate” to “appropriate”, or some simple numerical scale (1 to 10, say).

Examples are easy enough to find:  SurveyMonkey gives you a sample page of a visual preference survey.   For that one it’s a five-point scale.  Here’s one that illustrates several different types of contrasts.   They can also be done with paired pictures, where you just pick the one you prefer, like  this one or this one.  Here’s an example of what the results could look like.  And I’ll just link to a few more random examples here, here, here, here, and here.

My point with the illustrations above is that “visual preference survey” is not some well-defined method.  It’s a wide-open, anything-goes approach.  Often the main point is not to gather data, but to have “community engagement” in the development, i.e. purely to allow citizens some ill-defined input to the process.

There are several obvious problems and pitfalls in using this approach.  Let me list them out.


First, the design of the survey itself — the choice of pictures, and the rating method — is a black box controlled by Town staff, with input from the Board of Architectural Review (BAR).

Wikipedia lists a quote that more or less sums up the issue:

“when you show citizens stark images of new suburban subdivisions or strip centers versus beautified images from America’s finest small towns, the outcome is predictable and largely meaningless.” 

So, for example, if shown pictures of buildings …

  •  with streets full of traffic in front of them versus empty streets;
  • photographed on sunny days versus buildings photographed on overcast days;
  • with utility lines in front versus utility lines missing;
  • in good repair versus poor repair;

… there’s a good chance that survey respondents will rate the prettier picture higher, regardless of the structure of the building.

The bottom line is that most people end up rating the buildings on overall attractiveness.  A researcher can intentionally or unintentionally bias the results by varying the “prettiness” of the scene with the desired building characteristics.  So, e.g., if shown a series of ugly small buildings and beautiful large buildings, a person who objectively wanted small buildings might be fooled into rating the tall buildings more highly.

To be clear, in a survey using actual pictures of buildings, you may or may not know what the researcher is attempting to measure with any given set of pictures.  For example, a researcher might show you a series of buildings with and without canopies at the entrance door, and you might be rating them on the attractiveness of their color scheme.

This is why some visual preference surveys use computer generated images to isolate the characteristic that they want to you judge.  The more modern approach is NOT to compare pictures of different buildings that vary based on some characteristic, but to use computer-generated or Photoshopped images that vary by a single characteristic at a time.  E.g., if the Town wanted your opinion on building heights, they’d show you pictures of buildings that only varied in height, not in any other way.

It does not sound like the Town of Vienna survey will do that.  The first task appears to be agreeing on a set of pictures with the Board of Architectural Review.

Edit 9/27/2018:  Because of this, I think my minimum due diligence is to audit the survey for balance.  That is, are tall buildings and short buildings depicted in roughly the same way?  Or are the picture of tall buildings “beautiful” and the short buildings “ugly”?

Objectively, there are some commonly used visual cues for “beautiful” and “ugly” urban scenes.

On the ugly side, we would have:

  • Traffic, crowds, people pushing along crowded sidewalks.
  • Overhead power lines.
  • Adults and the elderly.
  • Inclement weather, overcast sky.
  • Dirt, trash, indications of poor repair (e.g., peeling paint).
  • No or sparse landscaping.
  • No pools, fountains, or other water features.
  • Dull color field (browns, blacks, grays).
  • Middle-aged buildings — not new, not old enough to be quaint.

On the beautiful side we would see:

  • Empty streets or little traffic, a few individuals relaxing, eating, etc.
  • No power lines visible.
  • Children and pets.
  • Sunshine and blue sky.
  • No evidence of litter, dirt, or surfaces in need of repair.
  • Abundant green space and blooming flowers.
  • Pools, fountains, and other water features.
  • Bright color field with vibrant colors.
  • New buildings and quaint old buildings.

It will be simple enough to split the pictures of buildings into tall (four story) an and short (3 or fewer stories), and calculate the average rate at which ugly and beautiful clues occur for the two groups of pictures.    This is a perfect little project for crowd-sourcing via Surveymonkey.


Second, the use of the results — how the ratings of the pictures will be translated into a guide, and possibly to changes in MAC zoning law — is a black box controlled by Town staff.  Consumer preference surveys tend to produce modest and often inconsistent differences in the best of times.  What, exactly, will the Town do with that information?

Just think about it for a second and you’ll see what I mean.  Let’s say that, on average, four-floor buildings were rated 0.5 point lower than three-floor buildings, on average, on a scale of 1 to 5.  How, exactly, does that translate into a design guideline?   Would MAC then be changed to allow only three floor buildings?  Would builders get some sort of credit for only building three floors?

There’s no answer to that.  There is no well-defined way to translate ratings into design guidelines or zoning rule changes.  That’s entirely subjective.  So, what the Town actually decides to do with that information is … entirely up to the Town.


Third, the size of the buildings is a big problem for a lot of people, but there won’t be any scales on these pictures.   A “four floor” building can be less than 40 feet tall (typical), or it can be 62 feet tall (as allowed under MAC).  Siting that building 10′ from the curb results in far more of a “canyon” effect than siting it 30′ from the curb.


Fourth, the results will be used to “inform” a set of voluntary guidelines.  For example, even if tall buildings are universally hated, there’s no plan to reduce the maximum building height under MAC.   We will still have the profit motive driving builders to construct the largest building that will fit on the lot.  Compared to that, any “visual guidelines” would be a slender reed, indeed.


Fifth, the technical approach to conducting the survey — inviting people to take it on-line via social media — does not guarantee unbiased results.  E.g., if older residents are less likely to use or respond to social media, and they strongly dislike large buildings, that dislike will be missed under this survey design.  This is a well-known problem with surveys of this type and can lead to significant mis-statement of public opinion even for straightforward yes/no questions.

Why you will never see a study of the impact of MAC on traffic, 9/22/2018, edited 10/4

Did you know that:

  • When MAC was first being discussed, numerous citizens called on the Town Council to do a study of the impact of MAC on traffic.
  • Town Council passed MAC anyway, without such a study.
  • But at that time, the Town Council promised to commission such a study.
  • And they never did  — they just let it slide.

All of this is courtesy of an exchange I had yesterday with a fellow who has been tracking MAC zoning since its inception.  If I can find hard evidence on the Town Website, I’ll add the appropriate links to the text above.

So let’s connect the dots.

  • When MAC was being developed, the MAC steering committee was forbidden to look at traffic as an issue.
  • Next, the consultants that the Town hired to help develop MAC were instructed not to look at traffic.
  • Then, despite pleas from the citizens, the Town refused to commission a study of traffic, and MAC was adopted anyway.
  • At that time, the Town promised to do such a study of traffic.
  • The Town then reneged on that promise.
  • Fast forward to the present, and Councilman Noble has called for an overall Maple Avenue/MAC traffic study as part of the temporary moratorium on MAC submissions.
  • And the Mayor ignored that when she summed up what was going to be done during the moratorium.

Do you see a pattern here?

Let me explain why the Mayor and pro-MAC Town Council members can’t afford to let that traffic study be done.   In a nutshell, any competent study will show that, in the long run, MAC is going to make Maple Avenue traffic significantly worse.  And they can’t afford to admit that.  So they have to prevent anyone from saying that officially.

And so, in what appears to be standard operating mode, the Mayor did not say “no” to the traffic study.  She just ignored it.  Just as the Town ignored its prior promise to do such a study.

The details of the long-run impact of MAC on traffic are laid out on this page  You can also read my criticism of the Mayor’s rhetoric on traffic, here.   But the key table is this.  This is just traffic from the additional housing on Maple (i.e., ignoring traffic to the retail spaces), under the assumption that 70% of the MAC-eligible acreage on Maple eventually gets redeveloped under MAC.

The point of showing all these scenarios is this:  Any competent analysis of the long-run impact of MAC will show that MAC will make traffic materially worse.  The table above is not rocket science.  All I did was scale up the builder’s figures for the housing-related trips for 444 Maple Avenue West/Tequila Grande.  And then change a few of the assumptions.  And the basic concept isn’t exactly rocket science either — add a few thousand new residents, all of them on Maple, and … seriously, what do you think is going to happen to traffic?

If I can figure this out, I would assume that anybody even remotely familiar with traffic estimates would know this.  And that’s why the Mayor and Town Council never have and never will allow that study to be done.  They’ll talk about it, they’ll promise to do it.  But the pro-MAC Town Council members simply can’t afford to allow an honest and competent study of MAC and traffic to be done.

Finally, when in doubt, pay attention to what they do, not what they say.  And what they are doing is getting ready for a lot more cars downtown. 

EDIT 10/4/2018:  The current Town Budget showed plans for spending $6 million to build a parking garage on the Patrick Henry Library lot, and raising the meals tax from 3% to 4% to pay for that.  But the most recent capital spending plan revised that.  The spending for the library parking garage was dropped, and the increase in the meals tax was dropped.  So, while what I say below is still true in the long run — they Town has funded the feasibility study for the library garage — the schedule is now delayed.  

Original text follows:

Between the Mill Street Garage and the proposed Patrick Henry Library garage, the town is funding (in part) the creation of about 550 new parking spaces in the downtown core.  (Mill street has about 125 for the Town on the 2nd floor, and another 125 or so privately owned on the ground floor, plus parking to support the retail space; Patrick Henry will have 350, but will replace the existing 50-or so that are there, for a net 300 new.)  Just for comparison, the Giant Food shopping center lot has about 600 spaces total (yes, I counted them via Google Maps.)

So, in round numbers, Town Council is arranging to add parking more-or-less equivalent to the entire Giant Food shopping center lot, all of it downtown.  You can’t do that, and then say, with a straight face, no, we’re not expecting to see any more traffic.

I have to admit, though, that when I hear the phrase “charming small town”, the first thing that comes to mind is a four-floor concrete parking structure on the main street.