Post #876: Town of Vienna, please see the forest through the trees.

This will be of no interest to anyone outside of the Town of Vienna.  Unless you are a student of how “silo thinking” can lead to truly inefficient decisions.

Let me cut to the chase.  The Town of Vienna is using a $16M piece of land to produce (arguably) $20,000 in annual cost savings to the Town.  Probably, less than that.  And using that in such a way that, in practice, prevents any better use of that valuable property for benefit of Town residents in general. Continue reading Post #876: Town of Vienna, please see the forest through the trees.

Post #697: Town elections, see Post #508

See Post #508, from January 9, 2020 and earlier, on splitting the vote and political suicide.  My numbers were a little off.  But not much.

Votes Percent
Colbert 1545 43%
Majdi 1172 33%
Springsteen 869 24%
Total 3586 100%

Post #511: Three followups to the last Town Council work session

Source of this image is linked here.

This is about three unrelated points from the Monday Town Council work session that, in hindsight, struck me as possibly worth writing up:  The Town traffic simulation, the treatment of the Town strategic “plan”, and the end game 18 to 24 months from now.

Town traffic simulation.

Part of the Town’s “Multimodal” traffic study estimated the impact on traffic congestion from Maple Avenue development.  I’ve spent a lot of time trying to figure out what the consultants did to arrive at their numbers.  As of last night’s meeting, I have officially given up on that, because I can’t make head or tail out of it.

But I did take away one thing from trying to puzzle that out:  There’s a lot of uncertainty (wiggle room) in that calculation.  That’s worth noting, I think.  See if you can follow this.

  1. Back in August, the contractor presented results showing 758 additional net new evening rush-hour trips from Maple Avenue redevelopment.  They did not talk about it during that presentation, or during their next presentation.  But it was on a slide that they skipped over (Post #358).
  2. One issue I had with that is their “baseline” traffic, i.e., the number of trips that they assumed occurs right now.  Their graphic clearly showed that they assumed that (e.g.) currently-empty buildings were generating traffic on Maple.
  3. The single worst example of that was the assumption that the Suntrust Bank (east) currently gets 381 trips in the afternoon rush hour.  As previously noted, that’s a ludicrous number — it amounts to one car going into or out of that bank parking lot every 10 seconds.  Councilman Majdi called them out on that, but both the contractor and Town Manager strongly defended that as “science”.  I was so ticked by that misuse of the term “science” that I sat in the bank parking lot and counted cars to demonstrate that the actual traffic to that building was about one-tenth of that (Post #465).
  4. When I want to look at the final report, I couldn’t find those 381 trips.  As it turns out, at yesterday’s work session, it was revealed that the contractor removed those 381 existing trips from the baseline.  Simply zeroed them out.  That’s why they are no longer in the report. And so, presumably, we have no further cause for complaint.
  5. OK, fine, I can do arithmetic.  If they remove 381 from the baseline, that should then add 381 to the net new trips.  (Why?  Because you net out the existing traffic, when calculating the net new traffic.  If you reduce existing traffic by 381, then you should have increased the net new traffic from development by 381.
  6. And yet … in the final report, the net new trips from Maple Avenue actually decreased from 758 to 500.

So, without pondering how they justified that, just do the math.  Focus on the simple arithmetic of how they had to have gotten from the prior estimate to the current estimate.  Solve for X:  758 + 381 + X = 500.  Turns out, X = -639.  That is, they managed to extract a further 639 net new trips out of their analysis, to get from the original estimate that (presumably) netted out the Suntrust 381 in the baseline, to the final estimate that did not.  Just as a matter of arithmetic.

This X factor of -639 trips is what economists call a structural uncertainty in the estimate (as opposed to a statistical uncertainty).  It’s the uncertainty that arises from doing the numbers one plausible way versus another (as opposed to a more traditional statistical uncertainty, which arises from purely random factors, so to speak).

So this lower bound for the true stuctural uncertainty of the estimate — how much it changes based on choices made by the analyst — is larger than the estimate itself.

A lot of other things about the methods and results looked counterintuitive to me.  For example, the net new traffic during the AM rush hour, to the extent that it left Vienna, flowed mostly westward (i.e., against the direction of morning rush hour traffic).  About 2.5x as many additional cars exited Vienna at Nutley as at Follin.  But put those issues aside.  The simple arithmetic of getting from the draft to the final — the X above — is what convinced me that I would never have any real understanding of how they arrived at their numbers.

So this is truly a black box, and a black box it shall remain.  There are open-source software packages that allows individuals to model transportation networks (e.g., here, here, or here.)  All of them require considerable amounts of data as input (e.g., traffic light timings, traffic counts).  I’m not going to put in the effort to try to gin up my own estimate.  But my conclusion is that this is the only way to avoid having the results be a total black box.

Addendum:  Traffic counts and the K-Q curve.

Addendum:  I also have no clue what these traffic models do when actual traffic passes the peak of the “K-Q curve”.  (Briefly, as you try to stuff more and more vehicles through a given roadway (increase the density of cars per square foot, traditionally represented by “K”), each individual car may move more slowly, but in aggregate, the total flow of cars (represented by the letter “Q”) increases.  That is, at first, each car may move slower, but you get more total cars moving through the road segment.  But as you continue to add cars, you reach a point where the reverse is true:  You get so crowded that adding more cars actually reduces total traffic flow.  Not only does each car move more slowly, but you actually get fewer total cars to pass through the road segment in a given amount of time.  That point — where jamming more cars onto the road actually begins to reduce not just speed, but total traffic flow — that’s the peak of the K-Q curve, as in this diagram (k = density of cars, q = total flow of cars through the roadway, v = average car speed).

Source:  Wikipedia.

As I understand it, this is the reason you will see (e.g.) metered on-ramps (ramps with traffic lights) at the on-ramps to the inside-the-beltway portion of I-66.  They are trying to avoid passing the peak of the K-Q curve.   Once you pass that peak, you are helping nobody by allowing more cars onto the roadway.  Not only does every individual car move slower, but you actually get fewer total cars to pass down the highway in a given amount of time.  All you do is increase the size of the backup.

It sure seems to me that we hit the peak of the K-Q curve during morning rush hour.  At least sometimes.  At the point where traffic from the Courthouse and Maple light backs up all the way to Nutley, it’s tough for me to imagine what we haven’t hit and passed the maximum possible through-put of the Maple-Courthouse intersection.  Here we are, just before 9 AM, looking east and west on Maple, at the Nutley Street intersection.

But here’s the technical question.  Look at the diagram above and think of the curved line as a hill.  In terms of traffic counts, you get the same traffic count if you are halfway up the upslope of the hill (before the peak of the K-Q curve, where traffic is light and moving well) as you do halfway down the downslope side of the hill (past the peak, where traffic is packed and moving slowly).

I think this explains one oddity of the report, in that the consultants seem to think that we have one long rush hour period from about 8 AM to about noon.  Because they are looking at the traffic counts, and the flow of cars is about the same throughout that period.  Like so:  The flow of traffic (cars/hour) is the same at 9 AM as it is at 11 AM.

Source:  Vienna multimodal transit report, 12/20/2019 draft, page 3-13.

But as anyone who drives that road can tell you, there’s a stark difference in the level of traffic queues or waiting times between 9 AM and 11 AM.  Just before 9, traffic routinely looks like the pictures above.  Whereas around 11 AM, traffic flows far more freely.  But you see no difference on the graph above, because the traffic counts, by themselves, are blind to the fact that Maple hits capacity during the rush hour.  The count you get when you are on the downslope side of the K-Q curve (just before 9 AM, with huge backups as pictured above) is the same as the count you get when you’re still on the upslope of the curve (around 11 AM say, when traffic moves pretty well).

So that’s just an oddity that I noticed.  Traffic counts (cars/hour) do not, by themselves, accurately measure traffic, because of the ambiguity caused by hitting the peak of the K-Q curve.  Very light traffic and very heavy traffic can generate identical traffic counts.  And the graph just above doesn’t show that we have one long rush hour.  It just shows that the total traffic counts don’t change much between the absolute peak of the AM crunch (which I place at about 8:45 AM) and the must less crowded mid-morning period.  I think that, as much as anything, demonstrates that we hit some measure of capacity on Maple during AM rush hour.  Once you hit capacity on Maple — as I infer that we due during the AM rush — additional traffic does not result in additional traffic counts.

I’ll mention one other truly weird possibility.  At this most recent meeting, Coucilman Noble made much out of the new traffic light system that Vienna is getting.  (I have the vague notion that VDOT, not the TOV, is responsible for that, but that doesn’t matter).  If that traffic light system actually increases throughput during the periods when Maple is at capacity (something that I doubt will happen, per discussion of capacity above, but is possible), then, by traffic counts alone, it will make it look as if traffic has gotten worse during rush hour.  That’s just another example of the way in which traffic counts, alone, can provide a misleading indicator of traffic when a road is at capacity.  If there’s a fundamental change in the roadway (in this case, new light timing), traffic (counts) going up can mean that traffic (wait times) is going down.

And as a final, final note on that, if the Town of Vienna wants Vienna citizens to be aware of some profound benefit they are going to get from new traffic signals, I suggest that they actually provide at least some sort of description of what they intend to do.  Near as I can tell, the entirety of what Vienna has to say about this project is a total of 23 words on this page on the Town of Vienna website.  Normally, as you may realize, I will do my homework to understand what the Town is about.  But from the description, I can’t even find the words to Google up what this is.


Town Strategic “Plan”

In theory (and by law), anything the Town of Vienna government does needs to comply with the Town’s strategic plan.  But if you look back at when the Town developed MAC zoning, they developed MAC zoning (2014), then rewrote the strategic plan (“mixed use development) to match it (2015-2016).

This more-than-begs the question of what you mean by “plan”, if you rewrite the plan to match what you subsequently decided to do.  I have a vague idea that it isn’t even remotely legal to do that.

That said, based on the last work session, that’s the plan going forward.  When Councilman Majdi brought up the idea of addressing the comprehensive plan first, that was (of course) immediately shot down.  The agreed-upon sequence is now to rewrite the zoning (with apparently no restrictions whatsoever), and then once again rewrite the comprehensive plan to match whatever comes out of the zoning rewrite, if necessary.

Just in passing, and to underscore how loosey-goosey this is, Town staff have now set it up so that this Town Council is actually providing less guidance to this process than occurred during the original development of MAC zoning.  At least, under MAC, Town Council somehow arrived at a firm limit on building height.  Here … near as I can tell, anything goes.  Town Council has not publicly agreed on even one single thing that they want to see in a revised MAC zoning.  It’s all up to the Department of Planning and Zoning.  That’s no surprise, given that Planning and Zoning appears to be controlling this process.

Looking 18 months down the road.

Fundamentally, the limit on the density of development on Maple Avenue appears to be a political limit.  It’s really about what the median Vienna voter wants.  There’s no technical barrier to filling Maple Avenue with Chick-fil-A-car-washes.  It’s just that the people who live here do not, on average, seem very fond of that idea, and they will vote for people who say they won’t do that.

This is all the more true if you purposefully ignore any other possible limits to growth.  E.g., if you will not discuss development in the context of the capacity of Maple to move traffic, or in the context of impacts on nearby residential neighborhoods.  Barring all that — if you acknowledge no other limits — then the only limit on the density of Maple Avenue development is a political limit.

This is a point that Councilman Majdi brought up at that work session.  And either his fellow Council members didn’t get it, or they just shot it down as sort of knee-jerk reaction.

So I need to point out the following:  Town staff have structured this process so that our elected officials have no say in shaping the new MAC.  They will have no formal input in what happens to MAC zoning until the very end of the process.  The process will be controlled by the Department of Planning and Zoning, with input from the Planning Commission (still largely staffed by holdovers from prior Town Council.)  Only at the very end of the process will Town Council be presented with the finished products.

Councilmember Patel tried to reverse that — to get Town Council to have first say over the shape of the revised MAC zoning — and got quashed by the pro-MAC members of Town Council.

So I’m just pointing out the disconnect here.  The only functional limit on MAC density is a political limit.  And our political body is (formally, at least) completely shut out of the process of shaping the new MAC, until the very end.

The only logical conclusion is that this is likely to end (or, at least, risks ending) in some sort of train wreck.  The people actually structuring the new MAC are not subject to any political constraint — they are not elected.  And the people who are elected are not part of the MAC-rewrite process.  That’s exactly what the response to Councilmember Patel established.  But in the end, the constraint on what can and can’t be done is a political one.   So this is a fundamental mis-alignment of incentives, and poor overlap between scope of authority and scope of responsibility.  Town Council is going to be responsible for what comes out of this process, but they have been stripped of all authority to shape it.  

What guarantees that Town Council will be handed a new MAC that is politically acceptable?  Nothing.  The process is literally and purposefully structured that way.  Any notion that Town Council would offer overall guidance (by having first crack at proposals) was firmly snuffed out at this past Town Council work session.

And that’s the scenario that I reckon as a train wreck.  Suppose the very-pro-development Department of Planning and Zoning, working in a political vacuum, comes up with a zoning proposal that appears unacceptable to the median Vienna voter.  Then what happens?

I believe that Town staff are actually counting on that possibility of train wreck.  That is, they are counting on being able to cram this down Town Council’s throats, at the end of the process, one way or the other.  They think that those who oppose larger buildings and higher-density development will blink, in order to avoid that train wreck.  (E.g., to avoid vetoing a proposal that too two years and a quarter-million-dollar contract to develop, and that includes a bunch of purely technical and non-controverial fixes to Town Code in addition to a rewritten MAC.)  By refusing to separate out the non-controversial “clean up” portion of this work, from the more controversial changes to Town zoning, they can given Town Council a one-vote take-it-or-leave it choice (as I have already noted, per Post #483 and others).

Or, possibly, they are hoping that this next election will lead to a change in the fortunes of the pro-MAC portion of Town Council.  So that by the time this comes to a vote, they’ll have the votes for a higher-density MAC zoning.  That’s certainly possible.  From what I can tell, the anti-MAC forces seem totally disorganized at this point.  I guess we’ll have to wait and see.

Post #324: Affordable housing (ADDENDUM AND FURTHER CORRECTION 7/24/2019)

Affordable housing is a weighty topic that requires a real depth of knowledge if you’re going to address it seriously.

This post, by contrast, is not a serious analysis of affordable housing.  This is just one of those quirky little things you stumble across doing a Google search, that, oddly enough, can be used to get across a few simple points.

Bottom line:  Vienna residence, furnished, utilities included.  Monthly rent is $1950 $1500.  Price includes utilities, internet and cable, as well as daily maid service and free continental breakfast.

Correction:  Turns out, a colleague knows people who have lived there.  If you prepay a week in advance, it’s just $50/night, which works out to $1500/month.

Trip Advisor breathlessly assures me that it’s the #1 rated! motel in Vienna, VA. True, by definition.

On a more serious note, how about a little arithmetic.  It looks like the Wolf Trap Motel has about 120 rooms, or “dwelling units” in this case.  Is there any hope that MAC zoning will ever provide even as many as 120 affordable housing units in Vienna? 

And by that I mean, actual, formally-defined affordable housing under some legally-administered program.  Not the fast-and-loose discussion of “the market-determined rent on these apartments will be more affordable” that has substituted for real Town public discussion of this issue so far.  (And if you have no clue what I’m talking about, in terms of a legally-defined affordable housing project, take a look at what they do in Falls Church.)

The arithmetic is easy enough:  Additional MAC dwelling units x % reserved for affordable housing = additional MAC affordable housing.  All we need are plausible estimates for each.

The table below works through all of that, projecting total dwelling units based on the current MAC average density of dwelling units per acre, and some assumed fraction of Maple that eventually undergoes redevelopment.

But what fraction of units might plausibly be affordable housing?  To model that, I took one of the recent Falls Church mixed use projects.  There, for the Broad and Washington Project, the developer proffered six percent of the units in the building for affordable housing (see this .pdf).  So, if they can do it, presumably we … might too.  (I think this figure is ballpark for the rest of the Falls Church mixed-use development.  E.g., five beds in the large Kensington assisted living facility in Falls Church are in a special affordability program.)

Reading down the table, the first three MAC projects come in at 41 units per acre.  You can then see counts of total additional units that would be built under assumptions that 30% or 70% of the total MAC acreage gets redeveloped at that density.  Finally, if 6% of all new units are set aside for affordable housing, you get the counts at the bottom:  64 affordable housing units if 30% of Maple is redeveloped, or 169 affordable housing units if 70% of Maple is redeveloped.

(N.B. for the number-oriented among you.  The acreage is not proportional to the percentages because I net out the 5.7 that have already been approved for mixed-use development.)

And so the answer to my question is, maybe, if all suns shine.  If Vienna actually had an affordable housing program.  If every mixed-use building from now on would proffer affordable units at the same rate as was seen in the model Falls Church project.  And if a very large fraction of Maple gets redeveloped.

If all that happened, you might get more affordable housing units out of MAC than there currently are rooms in the Wolf Trap Motel.

But:  You can’t get blood from a stone.  Put aside the fact that some projects would not be suitable for this program (e.g., the million-dollar condo townhouses at Marco Polo).  The bottom line remains that there is no free lunch.  Every one of those units is money out of the developers’ pockets, so affordable housing must be balanced against other competing demands for proffers.  For example, developers might not be able to afford both putting the utility lines underground and reserving 6% of units for affordable housing.  Ditto, providing significant public green space on their property and in additional supplying significant affordable housing.  And if a future MAC results in smaller buildings, there would be fewer units and less profit available from which to supply affordable housing.

My point is that instead of just talking in the abstract about affordable housing, we really ought to get into the numbers just a bit.  It’s instructive.  Best guess, any formal, legal, zoning-driven affordable housing program under MAC would be a drop in the bucket, relative to the perceived need for affordable housing.

My only other point is to study Falls Church, because, by definition, they’re doing  better at it than we are.  Interestingly, while Falls Church has this formal, legally-defined affordable housing program, they also make sure that people looking for affordable housing can find a comprehensive list of apartment and condo rental rates.  They put those right on their website, on the affordable housing page (here, .pdf.). Those aren’t “affordable housing” in the legal sense, they are just (presumably) the market rates on the cheapest housing options available in Falls Church.  And given the extremely limited supply of legally-defined affordable housing, the market rate is going to be what almost every person pays.  Like it or not.

So, no free lunch.  But maybe a free breakfast, for the time being.


I started out this post entirely tongue-in-cheek.  But I didn’t realize there was more truth here than I bargained for.  A colleague assures me that she knows of five or six people who do, in fact, use the Wolf Trap as the only affordable housing in town.  They all work food-service jobs on Maple Avenue, as far up the block as Whole Foods, don’t own cars, and walk to work, while living (presumably two-to-a-room, so 750/month/person?) at the Wolf Trap Motel.

So, in fact, Wolf Trap Motel does function as affordable housing in Vienna.  And that peculiar old motel out on Route 50 in Fairfax — the one that looks like a ship’s wheelhouse — apparently does the same for that area.  So the recycling of downscale hotels as affordable workers’ housing is not just limited to the Wolf Trap Hotel.

As a final note, yet another colleague assures me that the Wolf Trap is the most common way-station for the newly divorced in the area.   So, yeah, it does serve as affordable housing.  Maybe not as the Town intends it, but it serves as that all the same.

Post 226: #closethecurbcutsnow

The Town has made much about closing curb cuts (parking lot entrances) along Maple, under MAC.  And the consultants for the (thing formerly known as the) Maple Avenue traffic study (post #223) duly echoed this with extended reference to the many curb cuts on Maple.

At various times, these curb cuts have been blamed for a) slowing traffic, b) increasing vehicular accident rates, and c) endangering pedestrians on the sidewalk.  For the moment, let me put aside truth versus fiction in these claims, and ask a simple question:

If these Maple Avenue curb cuts are such a clear public menace, why hasn’t the Town already started getting rid of them?   The Town owns the sidewalk.  How can our elected officials idly stand by, when the menace of excess curb cuts stalks the Town, threatening our prosperity and our very lives?

That was sarcasm.  But it’s a legit question.  It’s a question that I naively asked.  Seriously, if curb cuts are so bad, why don’t they close some of them? And the answer to that shows you exactly how proponents of MAC zoning will tell you only what they want you to hear. And not the full story.

After some research, my conclusion is that, practically speaking, the only way the Town can close a curb cut is to stuff a whole bunch of high-density housing on the lot behind it (i.e., MAC rezoning).  And so, the only practical way to close a curb cut is to have a more people  turning on and off of Maple, during the rush hour periods.

Once you figure that out, then it’s clear that the full effect of “closing curb cuts on Maple” is not the rosy picture painted by the Town.  You have to pay for that curb cut closure by adding to traffic turning on and off Maple.  Anyone who tells you that “getting rid of curb cuts” is an unalloyed positive for the Town is pulling your leg.  To put it politely.

In fact, I’ll up the ante on this.  If a property owner voluntarily agreed to allow it,  the Town could close a Maple Avenue curb cut.  So, with all the mayhem now being attributed to curb cuts, has the Town done anything at all about them?  Has the Town systematically pressured Maple Avenue property owners about closing Maple Avenue curb cuts?   Has it offered (e.g.) a property tax incentive for closing off curb cuts?   Has it identified the ones apparently associated with high accident rates and developed policies targeting those specific locations?

In short, if this is such a problem, then has the Town done anything whatsoever to address it?  Other than to use it to flack MAC?

Detail follows.

Continue reading Post 226: #closethecurbcutsnow

Post #202: MAConomics 101

Please attend tonight’s meeting.

Today, Wednesday, 3/20/2019, at 7:30 PM in Town Hall, in what will probably be the first and last time ever, all three Town of Vienna governing bodies will meet in a joint work session.  The Town Council, Planning Commission and Board of Architectural Review will sit in the same room and look over proposed changes to MAC zoning regulation.  You can find the meeting materials on this web page. Continue reading Post #202: MAConomics 101

Building height and density, 3/16/2019

After attending every public meeting on this topic for the last two months, I would like to present my summary of the extent to which the Town has engaged in serious discussion, so far, about changing the height limit and imposing density (dwelling units per acre) limits for MAC buildings. Continue reading Building height and density, 3/16/2019


Edited 9/14/2018 to remove discussion of meetings prior to the 9/17/2019 Town Council meeting.

For the meeting on the August 20th, the text of the amendments is in red, here (.pdf).  This appears unchanged in the materials for the September 17 Town Council meeting.

Arguably the most important change was a proposal to set a limit on density (dwelling units per acre), with the possibilities shown here (.pdf).  As of now, in counting dwelling units, the Town proposes to make no distinctions among dwelling units, (e.g.) an efficiency apartment and a four-story 3200 square foot townhouse each count as one dwelling unit. Continue reading changes

Planning Commission Meeting Wednesday August 8, 2018

The Vienna Planning Commission will meet TONIGHT, Wednesday August 8, 2018, at 8 PM in Vienna Town Hall to discuss some modest proposed changes in Maple Avenue Commercial zoning.  This is the meeting where they should finalize any recommendations they may have about these changes, to be passed on to the Town Council.  Please place this on your calendar and plan to attend.

The meeting materials are this web page.  Probably the overriding issue is the potential for adding a density limit to MAC zoning — limiting the number of allowable dwelling units per acre. Continue reading Planning Commission Meeting Wednesday August 8, 2018