Post #456: Fairfax County’s 527 Plan for Maple Avenue

Posted on November 13, 2019

Source:  Linked from

I am not yet done posting about all the interesting items that popped up at the 11/7/2019 Town Council work session.  This post is about an offhand remark that Councilman Noble made, regarding the “Tysons 527 plan” for Maple Avenue.

I have to admit my ignorance here, because I had no clue what he meant.  But it sounded somewhat important.  So, after some digging, this turns out to be the long-rumored Fairfax County plan that calls for widening parts of Maple Avenue.  If you plan to be in Vienna a decade from now, it will be well worth your time to have a look at that.  The time frame for this report is the year 2030.

I cannot over-emphasize that this is all theoretical.  This is about dealing with somebody’s guess (projection) of traffic in the year 2030, based on a guess (projection) of additional development at Tysons.  As far as I can tell, nobody has any actual plan for doing any of this to Maple Avenue.  At least, for now.

So, first caveat:  These are not firm plans for anything.  Hence the picture at the top of the page.  I have no clue as to whether or not anyone could actually require that Route 123 be changed in this fashion.  I believe this is merely Fairfax County’s way of showing might be done, to certain Maple Avenue intersections, in response to the additional traffic load that Tysons development might create.

And, second caveat:  We may not get all this projected traffic after all.  Public discussion about this Chapter 527 filing brought up some opinions that the additional traffic wouldn’t flow down Maple at all.  These projections were made more than a decade ago.  And, for the last decade, there has been no increase in actual Maple Avenue traffic (Post #398).  In fact, if you download the spreadsheet, you can see that average daily traffic on Maple has declined slightly over the last decade or so.  So what you are looking at below is based on the opinion, of one set of traffic engineers, as to the impact that Tysons development would have on Maple.  Don’t get the impression that this is the only opinion, or that there isn’t a lot of uncertainty about that opinion, or that the projected additional Maple Avenue traffic must materialize.  So far, it hasn’t.

That said, as I have been hearing about this terrible report for years, I’m going to summarize what it says.  At the least, it shows you what some set of traffic engineers thought it would take to fix a couple of difficult intersections on Maple Avenue.  But keep the caveats above in mind.  The sections of this post describe:

Chapter 527 filing?

Start here, on the Virginia Department of Transportation (VDOT) website.  To paraphrase it, if a locality has a rezoning proposal that will substantially affect transportation on some state highway, they have to file plans with VDOT, including analysis of traffic impacts and proposed changes to the roads.  VDOT then offers advice and comments on the plan.

In so many words, if some change in zoning is going to dump a bunch of new traffic on a state highway, you have to talk to VDOT first.  And the way you do that is spelled out in Chapter 527 of Commonwealth statute.  Hence, 527 plan.

When Fairfax County created plans for major development in the Tysons area, they had to file such a 527 plan.  So, is NOT Vienna’s plan, this is Fairfax County’s plan.  Click the links on this page on the Fairfax County website to access .pdf copies of the 2009 527 filing for Tysons.

(As a side note, if you read the regulation itself (.pdf), a locality does not have to file a Section 527 plan if it maintains the highway, rather than VDOT.  So, because Vienna maintains our stretch of 123 (using state funds), my interpretation is that Vienna did not have to file such as 527 plan to assess the impact of MAC rezoning.  This, presumably, is how they managed to pass MAC with no assessment of the impact on traffic.)


Vienna only appears in the Tysons’ 527 filing as part of the “neighborhood impact analysis”.  The point of this part of the plan was to see whether nearby intersections were likely to “fail” as a result of the additional traffic from Tysons development.  If so, they had to show how they would redesign those intersections to maintain an acceptable “level of service”.  In other words, if the additional traffic was projected to cause a new problem in the adjacent area, they had to show how they would fix that, and how much that would cost.

Definition of failing:  If an intersection has a traffic light, it is considered “failing” if the average rush hour waiting time exceeded 55 seconds (i.e., worse than level of service (LOS) D, see table below).  So, E and F for intersections with traffic lights.    Without a light, an intersection was considered failing if the worst delay in any direction averaged 100 seconds or more (Tysons 527 filing (.pdf), physical page 158).  That’s all measured separately for the peak hour of AM and PM traffic.

Source:  Wikipedia article on level of service.

They looked at four intersections in Vienna.  There is no explanation of why they only looked at four, and why they chose that particular set of four.  The entire description of the selection process is:  “Working with the local communities, FCDOT selected nineteen (19) intersections for assessment in this study.”  (n.b. FCDOT is Fairfax County Department of Transportation).

Those four intersections are show as  numbers 16 – 19 on the following table, extracted from physical page 143 of the Tysons 527 filing cited above.  This table shows the level of service (LOS) at these four intersections for AM and PM rush hour.  You have current (2008) conditions (white), a lower-development scenario (pink), and higher-development scenario (green).  Within each scenario, you see the level of service that would occur with no improvements, and then the level of service if they improved (widened) the intersection in some fashion.


Reading across the table for Beulah and Maple:  Right now (white columns), that intersection fails in the PM rush hour (level of service F).  If nothing is done, it will continue to fail in the PM rush hour under either development scenario.  But if they re-work the intersection (as shown in the next section), they could bring that up to a level of service D.

The other intersections read similarly.  Lawyers and Maple fails in both AM and PM rush hours now.  In theory, with improvements, that could be brought up to level of service D under the low-development scenario.  But it would continue to fail (level of service E) under the high-development scenario.  Westbriar and Old Courthouse fails now during PM rush hour, but could be brought up to level of service B or D if the intersection were improved.


For the three intersections that they studied and found problems with, what does the proposed fix look like?  Here I’m going to show the pictures for fixing these intersections under the high traffic scenario.  So these are the most invasive fixes shown.  Less would be done under the low-traffic scenario.  Additions to the roadway show up in color.  If you want to see more detail, you should look at the Chapter 527 report itself (.pdf).

In these pictures, the thin red line marks the current right-of-way.  Any time you see a thin teal line (this color), that marks the edge of private property that would have to be condemned to allow for widening of the right-of-way.  (So teal doesn’t show the area of private property to be seized, it just shows where the edge of the expanded right-of-way would be.)

Beulah and Maple, physical page 213 in the Tysons’ Chapter 527 plan.  Maple runs vertically (Tysons would be at the top), Beulah is at the left.  Under this scenario, Beulah would be widened by two lanes.  Maple would be widened by two lanes above Beulah and one lane below Beulah.

Lawyers and Maple, physical page 215 in the Tysons’ Chapter 527 plan.  Maple runs vertically (Tysons would be at the top), Lawyers (left) and Courthouse (right) run diagonally.  Courthouse is mis-labeled as Lawyers in this picture. This proposal would widen Maple by two lanes, Lawyers by two lanes, and Courthouse by one lane.

Old Courthouse and Westbriar, physical page 217 in the Tysons’ Chapter 527 plan.  In this orientation, the golf course would be just off the left side of the picture.  This proposal would widen put a traffic light at that intersection and a turn lane on Westbriar Court.


Once again, these are not any hard plans for anything.  They are a set of fixes that one set of traffic engineers thought would take are of additional Vienna traffic generated by Tysons development.  They are based on projected increases in traffic through 2030, and, so far, those traffic increases have failed to materialize on Maple.

Taken at face value, this 527 proposal was not quite as horrific as it had been rumored to be.  What I had heard described was something akin to adding two lanes down the entire length of Maple.  But the actual plan only widens the road at two key intersections.

That said, I think the fear may be that they only looked at two intersections on Maple.  If the projected traffic increase actually occurred, there’s no telling what, if anything, they would recommend for the rest of Maple Avenue.  Possibly, if they looked along the length of Maple, they’d suggest changes like that along the length of Maple.  If that ended up as the plan, the Town of Vienna would never be the same again.

There’s also a historical interest in this report, because as I hear it, at the time, it scared the heck out of Vienna’s Town Council.  And so — again, purely by rumor — some of the motivation for MAC was to plant some big new expensive buildings right up against Maple Avenue, and make it prohibitively expensive for VDOT to widen Maple in Vienna.  I’m not sure I believe that, I’m just passing along what I heard.