Author: chogan@directresearch.com

Post #368: Revising the commercial zoning regulations

At the 8/19/2019 Vienna Town Council meeting, there was a seemingly innocuous item listed on the agenda as “Directive to Town staff to research amending requirements related to commercial parking, parking lot landscaping, and streetscape.”

If you walk through the meeting materials for this item — which you can, as of this writing, access at this URL  — it still looks fairly cut-and-dried.  At issue were a handful of items such as the amount of parking required for commercial buildings, the nature and type of any required landscaping for parking lots, and the MAC “streetscape” requirements including broad brick sidewalks.

Although the language of the motion was not provided in advance, once you got to hear it, it still seemed fairly — eh — boring, for want of a better word.  Cut-and-dried.   Here’s Councilman Majdi’s motion, which I am pretty sure I transcribed word-for-word, from the tape:

“I move to direct town staff to draft amendments to the MAC as its top priority, and simultaneously to consider amendments to the regular commercial code: C1, C1A, C1B, and C2, in Chapter 18 of Town Code that affect the MAC.  I further move to direct staff to draft amendments to the regular commercial code that require the MAC streetscape, require landscaping for parking lots, and direct staff to consider changes to parking requirements or other incentives to encourage economic growth on Maple avenue, when drafting these amendments.”

In the end, that passed 4-3, with (what I characterize as) the remaining pro-MAC Town Council members (DiRocco, Noble, Colbert) voting against.

And yet, while I’m not seeing some fantastic controversy there, discussion lasted for an hour and a quarter.  I really don’t understand what went on.  There was an hour of discussion before they even heard the language of the motion.  At that point, the Mayor invited an audience member to get up and speak.  (This was not a public hearing, so how that was legal, I have no clue.)  Then immediately after that, they voted.

It just struck me as a strange session all around.   Like more was being not said than said.  So I’m just going to flag this one, putting a marker down in case, at some point, it becomes clear what happened.

At the end of this, I’ll give my best guess as to what is going on.  Let me emphasize that the final section here is pure guesswork.  Best guess, this was an attempt to focus the scope of (at least the initial) rewrite of the Town’s zoning ordinance to a handful of items that might be viewed as critical to Maple Avenue development.  And, as importantly, not to give Town Staff license to rewrite every aspect of the zoning ordinance. 

Continue reading Post #368: Revising the commercial zoning regulations

Post #367: The Patrick Henry Library/parking garage

At the 8/19/2019 Town Council meeting, consultants presented some drawings and other information for a replacement for the Patrick Henry Library.  You can find the meeting materials at this link, including the consultant’s initial report at this link (.pdf).   All drawings and analysis presented below are taken or summarized from the consultant’s report, architectural firm Grimm and Parker (G&P).

Patrick Henry Library has 61 parking places (G&P, page 6).  More-or-less everyone I have talked to says that’s inadequate, and that parking is a problem at peak periods or when the library holds some sort of event.  The library system would like to see 125 spaces at the new library.

There are currently three options on the table, labeled A, B1, and B2 in the report.  All include a new library that is about 50% larger than the current building, by floor area (21,000 square feet, compared to the current ~14,000 square feet).  The only functional difference among the options is the parking, which then drives the overall size of the entire structure.

Here’s an abbreviated version of the table showing proposed parking, for the three alternatives (A, B1, B2). (G&P, page 6):

Option A:  A narrow two-story building with surface parking

Option A would replace the current library with a two-story building on a smaller footprint.  You would end up with a narrower, two-story building.  This frees up enough ground space to expand surface parking to 90 slots.  The architects envision a “modern” building (G&P, page 11), but that’s just their stylistic choice.  You could as easily have a more traditional-looking building.  The only functional requirement is that it be a two-story building having roughly that footprint.

That picture doesn’t really provide the right perspective to see this building, relative to the existing library building.  Where the existing library ends about halfway across the lot, the new one would end about a third of the way across the lot.

Options B1 and B2:  One story-library building with parking garage on top.

Options B1 and B2 would replace the current library with a larger one-story building, then build a parking garage on top of that.  In both cases, the entire structure would more-or-less cover the lot.  The library itself would stretch about halfway across the current lot.  The rest of the lot would be some surface parking and access to the parking garage above.  B1 would add one floor of parking, B2 would add two floors of parking.  The B2 option would require a zoning variance to be allowed to exceed the 35′ height restriction for C2 zoning.

Here are the pictures, (G&P, page 13, G&P, page 14):

The look of the building is again merely the architect’s choice, and is not a necessary part of the design.  The library itself is made to look like a bunch of shops, and the building has the pseudo-many-separate-buildings facade that seems mandatory for MAC mixed-use construction.

Discussion

First, I have copied the Town’s recording of the discussion of this item and have posted that to Youtube.  You can access it below.

A few opinions:

Option A is probably dead in the water from the lack of parking, relative to the projected need for parking.  Fairfax could build that if they wished, without Town of Vienna participation.  Some Fairfax libraries have more parking per square foot than the 90 slots projected under Option A.  Some have less.  But given that Fairfax County’s own projected need is ~125 slots, my guess is, Option A, as described, is unlikely to be built.

Putting aside the looks of the buildings, I thought a few things were missing from the consultant’s discussion of options B1 and B2.

Underground parking is a way to reduce the impact of this new structure.  Absolutely every mixed-use MAC building proposed so far has underground parking.  My understanding is that this is modestly more expensive than above-ground parking.  But when you see every for-profit entity opting for that, you have to ask why that was not considered here.  You could have (e.g.) a two-story building with as much parking as option B2 if you put one floor underground.  You could have adequate total parking under option A by burying another level of parking under the surface parking.

Underground parking tends to be … well, creepy.  But above-ground parking garages are typically ugly.  In this case, we’d be erecting a parking garage, on the main street, in the center of Town.  A large municipal parking garage directly on the main street does not say “small town” to me.  So all other things equal, I’d work to minimize the impact of that.

Limited vertical clearance is another way to shrink the parking structure.  Some Fairfax County library parking garages were built with parking with limited vertical clearances.  For example, the City of Fairfax regional library has a 6’8″ limit on vehicle height in the parking garage.   I assume that was to allow the building to blend in with its surroundings and not dominate them.   So you might be able to have a lower three-story building with that option.

What parking need is there within a quarter-mile radius?  City planners often use a quarter-mile as the longest walk that customers are typically willing to make to get from parking to a store.  Below is the quarter-mile radius around the Patrick Henry library, from Calcmaps.com.  By eye, in terms of areas with scant parking, this would provide parking for a) the entire Church Street commercial district, b) the under-parked shopping center at Maple and Center (former Starbucks), and the under-parked shopping center at Maple and Park (Chipotle).

So I’d start with that an estimate of projected need.  And I’d also discuss the advantages and disadvantages of, in effect, bailing out those under-parked properties at taxpayer expense.

Is this part of a larger picture, or is it here solely to serve local-area parking needs?  For example, does the Town anticipate running a “circulator bus” out of this parking garage (See Post #362).  Could this be a “transit hub” for individuals transferring from cars to public transit during the AM and PM rush hours?  This would have to be added to the estimated local parking demand.

It would probably be quieter, possibly be nicer, and might be cheaper to put the library on top of the parking.  You probably lose some parking this way, but my experience is that vehicle noise transmits right through the arched pre-stressed concrete floors of parking garages.  (Thump-thump).  I note that the City of Fairfax library has the library on top, but that building is built into a hillside.   And with that design, only two floors would need to be built heavily enough to withstand the weight of the cars.

In this regard, I wonder about the extent to which the proposed designs for B1 and B2 are left-overs from when this was going to be built under MAC zoning.  I.e., is the library is at the bottom, disguised as shops, mostly to blend in with the rest of MAC mixed-use development?  If that’s the case, then it would be a shame to lock in this garage-over-library design without at least considering the alternative.  It would also be a shame to do it without finding some real-world examples of this construction (library under parking garage) and asking how that worked out.

 

Post #365: Post 360, rescinded

My Post #360 is incorrect.  At that time, it appeared that the Town was no longer posting recordings of work sessions for (e.g.) Town Council or Planning Commission.  The Town has now posted all of the recent work session recordings, so what I wrote in Post #360 is not correct.

If you want to know what was said in a recent meeting or work session by the Town Council, Planning Commission, Board of Architectural Review, or Board of Zoning Appeals, you can look at the Town’s Granicus calendar page, at this URL.

If you are interested in any other meetings, you might find some (but not all) in the archives section at the bottom of this page on the Town of Vienna website.

Post #364: Curiouser and curiouser, or, uncertainties in projecting traffic

This post points out a few major uncertainties in projecting likely traffic impacts from Maple avenue redevelopment.  It’s the last thing I plan to write about the Town’s multimodal transit study.

To cut to the chase, if somebody tries to convince you that these estimates are Science, and Should Not Be Questioned, just laugh at them.  Because the closer you look, the cruder and more divorced from reality these projection methods appear to be.  And then the actual real-world complexities of traffic have to get layered on top of that.

I’ll start out by telling you why these studies systematically understate the actual impact of redevelopment on traffic.  With a seemingly absurd illustration, right from the contractor’s report.  In a way that I think everybody can understand.  Click here if that’s all you care to read that section, a discussion of selection bias.  After that, I move on to more complex issues.

But you might also want to check out the final and purely speculative section, which asks whether traffic seeks its own level.  Maybe Maple is about as intolerable as it can get.  If so, and we add a bunch of housing/commuters to Maple, well, something’s got to give.  And maybe that something will be people who used to shop on Maple, going elsewhere.  Maybe, in the end, converting our commercial district to housing will simply leave total traffic roughly unchanged, but displace shopping trips with commuting trips.  Guess that’s kind of a good news/bad news scenario.  Maple won’t be materially worse for traffic.  But businesses on Maple might not like the results.

Continue reading Post #364: Curiouser and curiouser, or, uncertainties in projecting traffic

Post #362: The Town’s multimodal transportation study, Part 2

This post looks superficially at what I consider to be some of the least-useful or most-puzzling suggestions in the Town’s multimodal transportation study.  My discussion of the big-picture issues for that study is in Post #359.  You can download the presentation summarizing the study here, from the Town’s website (.pdf).

What follows is not a systematic assessment.  It’s just a collection of the items I found most puzzling or most unlikely at the time.  Or the ones that just blithely assumed that (e.g.) existing parking and buildings could be eliminated.  So these show the proposal and my immediate response.

Detail follows

Continue reading Post #362: The Town’s multimodal transportation study, Part 2

Post #361: Yet a third cut at MAC-generated traffic

You might wonder how I managed to pick up on the Kimley-Horn traffic result  Post #358.  I mean, they did their best to flash that across the screen.  They provided more-or-less zero discussion.  None of the meeting participants said boo about it.

In fact, until I actually got my hands on the presentation, I thought I must have misread it, as you can see from the struck-out section of Post #357.  How could a result like that have been presented with no discussion?

But I remembered it because I was prepared to see it.   Or something very much like it.  Why?  Because the answer to the question “will MAC development add materially to Maple Avenue traffic” is pretty obviously “yes”.  I had already convinced myself of that more than a year ago.  Different methods will lead to different estimates, surely.  But even now, no matter how I slice it, that’s the answer I still come up with.

In this post I present yet a different calculation to suggest that this is plausible.  Just a rough cut, no real work involved.  I’m going to gin up a crude guess for the number of peak hour Maple Avenue trips you might expect, just from commuters living in all that new MAC housing.

Continue reading Post #361: Yet a third cut at MAC-generated traffic

Post #359: The Town’s multimodal transportation study, Part 1

In Post #358, I discussed what I saw as the single most important finding of the Town’s “Joint Maple Avenue Corridor Multimodal Transportation and Land Use Study“.  This post discusses the rest of that study, as presented at the Town Council (and PC and TSC) joint work session on 8/19/2019.

To cut to the chase:  There’s nothing (or almost nothing) useful in the rest of the report.  Not just because much of the detailed analysis was just-plain-wacky. It was, as I hope to discuss in a later post.  (Example:  Let’s let people park on Maple.)  But mostly, the basic approach was fundamentally wrong, in a way that prevents the Town from using the results to make rational decisions about Maple Avenue.  At best, I guess you might call it a place to start.  Or maybe a relatively inexpensive mistake, so that you know how to try to structure a usable study.

This posting is only about big-picture overview issues.  It’s already too long as is.  If I want to talk about the details, I’ll have to do yet another posting.

First, I’m posting my recording of this joint work session.

Why?  See Post #260.  Hope I’m wrong about that, but … just in case, my recording of the 7 PM 8/19/2019 work session is at this Google Drive link.

There’s no index, because it’s only 45 minutes.   Audio is lousy because there was poor microphone discipline, so it’s a mix of amplified and unamplified sound.  That requires a lot of post-processing (amplification, noise removal, compression) just to make it audible.  The heavy post-processing and low original volumes left a lot of artifacts in the recording.

But if you want to know what was said, and you weren’t there — sadly, looks like this is your one and only opportunity to do so.  See Post #260.

 

Continue reading Post #359: The Town’s multimodal transportation study, Part 1

Post #358: A one-third increase in Maple Avenue rush hour traffic.

The Kimley-Horn analysis presented at the 8/19/2019 Town Council work session estimated that even a modest amount of MAC development on Maple would result in (by my calculation) a one-third increase in peak rush hour traffic on Maple. 

I believe that’s the single most important fact to come out of the 8/19/2019 Town Council work session and meeting.  And yet, the contractor (Kimley-Horn) and the combined TC/PC/TSC blew past that so fast, nobody even bothered to discuss it.  So, since they didn’t talk about it, let me walk you through it.  With my usual citations as to sources and methods.

But first, I have to acknowledge a tremendous debt to Councilman Noble, who, as I recall, had to do everything short of pound his fist on the table to get this analysis included in this study.  I’m going to pile on the sarcasm later, but here, I am completely serious. This analysis was not part of the original proposal for this report.  But this is one of the numbers we must have, in order to have any rational discussion of what’s best for the Town of Vienna.  And if he hadn’t persisted, this would never have seen the light of day.  So, we, the citizens of the Town, owe Councilman Noble a debt of gratitude for prodding the Town into taking this step in the direction of having a rational, fact-based discussion of the future of Vienna under MAC.

Rational means discussing the pros and cons of your actions.  But the Town barred any discussion of traffic during the development of MAC.  So this action rights a long-standing error, and starts us down a path toward a rational discussion of the issues.

Detail follows.

Analysis

First you need a tiny bit of context in order to understand what the Kimley-Horn report showed.   That context is this:  How many cars pass down Maple Avenue, now, at the peak rush hour?  Answer:  About 2366 cars.

To be clear, that’s 2366 cars, passing a point on Maple, during that peak hour.  To see how I got that, turn to Virginia Department of Transportation traffic count data.  Download the 2018 Town of Vienna data from this link (.pdf).  Scroll to page 7.  Here it is with full detail.

Here it is again, simplified to just the key numbers.  (Sorry if you have to squint, this is how it looks in the .pdf from VDOT).

This is the street segment from Nutley to Follin.  At the far right is average weekday traffic of 33,000 vehicles per day.  Moving to the left is the “K factor” of 0.072, which is the fraction of daily traffic that was observed during the peak traffic hour.  (In this case we can tell that this number was an actual measurement by VDOT.)  Multiply the two together to arrive at (33000 x 0.072 =) 2366 vehicles during the peak rush hour, as measured by VDOT.

(The scientifically-trained among you will laugh at four significant digits for this number, but let’s just continue.)

OK, now you’re ready to understand the Kimley-Horn analysis.  First, get a copy of the Kimley-Horn 8/19/2019 presentation from the Town’s website, at this link (.pdf).  Turn to slide 10.  Without (yet) commenting on the quality of those numbers, let me just take them at face value. The key number is in boldface near the bottom:  +758 PM peak hour trips.

So, how much does rush hour traffic increase, under this scenario?  Well, that’s (758/2355 =) 32%. 

Or, in round numbers, a one-third increase in rush hour traffic.

A short break for some sarcasm.

Well, who could possibly have guessed that?  Who would have thought that concentrating a bunch of high-density housing projects on the single most congested street in Northern Virginia* might result in — more congestion?  Completely unexpected.

* OK, yeah, I made that up, about the single most congested street.  But if there were such an award, don’t we all think that Maple would be in the running for it?

Proper discussion.

First, the most important thing to realize is that this is only a partial build-out of all the available MAC property. The entire MAC zone contains 106 acres, more or less.  At the time MAC was passed, both Town Council and Town staff were cited as guessing that more than 60% of that acreage would eventually be redeveloped under MAC.

So, by eye, if you combined all the colored blocks on the picture above, what fraction of Maple was assumed to be redeveloped, for the Kimley-Horn estimate?  Knowing what I know about those lots, my guess is 20%.  So, this estimate says that if 20% of the MAC zone gets redeveloped under MAC, you’ll see a one-third increase in peak rush hour traffic.

By extrapolation, then, what the Town originally envisioned as a full build-out of MAC — 60%-ish of the entire MAC zone — would result in a doubling of peak rush-hour traffic.

You know, love MAC or hate MAC, that’s something we really need to think about.  Shame on those who forbade any discussion of traffic as MAC was being developed.  You did your Town no favors by doing that.  And, again, kudos to Councilman Noble for finally getting some numbers on the table.

Second, are there any obvious shortcomings of those Kimley-Horn numbers.  Yes, one leaps off the page:  Giant Food shopping center.  Look at the largest teal box on the picture above.  That’s the Giant Food shopping center.  They are claiming that redevelopment of that lot — all 10 acres of it — would result in just 65 additional rush-hour trips.

Hahahah.  No.  I would love to see the contortions they had to go through to get that number.  If they keep the retail — which you kind of hope they do, if you buy groceries in Vienna — then what you ought to see is the rush-hour trips generated by all the new housing.  So far, these MAC projects are averaging about 100 new Town residents per acre.  That’s a 10-acre lot.  So what you ought to see there is the Maple Avenue rush hour trips generated by maybe 1000 new persons, call that maybe 600 new adults, living on Maple.  I don’t think that just one-tenth of them will have jobs that require them to commute.

So, from a flat-footed common-sense perspective, it sure looks to me like they shaved that Giant shopping center number down.  Quite a lot.  There’s no telling whether that was a one-off, or whether all those projections were systematically shaved down.

Finally, can we “triangulate” this in any way?  That is, compare it to some independent estimate, done by some other method, to assure us that the Kimley-Horn estimate is in the ballpark?

Why do that?  There’s a lot of potential for slack in these traffic analyses.  A lot of potential for judgment calls.  And you’d like to see somebody else’s analysis to be sure there is no large systematic bias in the numbers.

I did my own crude estimate about a year ago, for total traffic (not rush hour), simply by extrapolating the 444 Maple West projections.  That’s my post titled “Traffic and the Ultimate Impact of MAC Zoning“, posted 7/26/2018.  Let me dig that up and compare to the Kimley-Horn estimate.

This is my crude estimate, from one year ago, impact on total (not rush hour) trips on Maple:

A year ago, I crudely estimated that a full build-out of MAC would increase total trips on Maple by 118%.  Extrapolating the Kimley-Horn number to a full build out of Maple implied an increase in total trips on Maple of 100%.  As these things go, that’s a bullseye.  My crude extrapolation and the Kimley-Horn numbers are definitely in the same ballpark.

I should probably mention other technical details and caveats that might materially matter, such as the treatment of “bypass” trips.  I should equivocate over the Chick-fil-A-car-wash number, because some fraction of those might never make it literally onto the segment of Maple between Nutley and Follin.  I should probably ask about the fraction of trips that might not make it to Maple at all, because I can’t know exactly what the Kimley-Horn analysis did.  (I assume that because this is about Maple, those are estimated Maple trips, but I can’t be sure of that.)  But let me stop here.  I think this is good enough for now.

I’m going end by repeating what I said more than a year ago, in the post cited just above.  If it sounds kind of strident, well, maybe in hindsight that was perfectly justified.

“The bottom line here is that under any reasonable set of assumptions, this is a significant and material issue, and the Town needs to stop avoiding it.  They need to look to the future, see what kind of Maple Avenue they are creating, and act now to avoid the worst impacts.  I can also understand why a pro-growth Town Council would not bother to do this basic calculation.  There is no way to paint a pretty picture here.  But the fact is, if the Town is bent on remaking Maple under MAC, they need to do this calculation properly and restructure MAC to give us something tolerable on Maple.  As it stands, there appear to be no long-term Town estimates of the ultimate impact of MAC.”

But now there are some estimates.  That’s progress.