Post #423: Town of Vienna, please add some pedestrian safety measures here (revised).

Posted on October 19, 2019

I think this is now the single most visually-obstructed entrance onto Maple Avenue, by a slight margin.  I’ll present details on that below.  All things considered, I think the Town ought to consider adding a few safety measures proactively.  Detail follows.

Note:  My original posting exaggerated the difference between the Chick-fil-A exit and another visually obstructed entrance on Maple.  This post is more nearly correct, based on more careful measurement.

I bike the Maple Avenue sidewalks all the time.  I my opinion, currently the single worst vehicle entrance, for obstructed view of the sidewalk, is the parking lot entrance between the Sunoco and the Vienna Mattress Firm.  Drivers cannot see past the wall of the building, and have to cross the sidewalk in order to see oncoming bicyclists.  As a bicyclist, I literally stop and poke my head around the corner before trying to cross that driveway.

By the numbers, that exit has better sight lines, to the sidewalk, than the Chick-fil-A exit will have.  The wall of that mattress store sits 12′ from the curb, versus 9′ for the Chick-fil-A transformer.  The driver’s eyes will sit about 13.5′ from that wall (based on a 21′ wide entranceway, centering the car in the outgoing lane.)  For the Chick-fil-A exit, the drivers eyes will be about 9′ from the transformer (based on 11′ lane width plus 2′ planting strip).  .

Crudely, here’s how the two sight lines compare, for a Prius about to enter Maple, with the front bumper just a the sidewalk.  (NOTE that all the numbers are correct, but in order to compare the two exits, I’m actually showing a mirror-image of the Chick-fil-A exitIn reality, the wall is on the other side of the eye for Chick-fil-A.)

I took a few measurements on my Prius to do this.  On a Prius:  Driver’s face to front bumper = 7′, center of driver’s face to left outside mirror = 2′, ground level to driver’s eye = 4′.  In addition, the driveway at the Vienna Mattress Firm appears to be 21′ wide, and the Chick-fil-A exit appears to be 11′ wide, with an additional 2′ planting strip between driveway and transformer.

In green is the sight line for a driver just about to enter the sidewalk at the Vienna Mattress store exit.  The driver sits 13′ from the wall, and 7′ from the sidewalk.  In red is the sight line for a driver just about to enter the sidewalk at the Chick-fil-A exit.  The driver sits 9′ from the transformer, and 7′ from the sidewalk.  (Again, note, the numbers are correct, but what I’m showing is a mirror-image of the actual Chick-fil-A exit.)

Assuming these dimensions are roughly correct, the driver at the Chick-fil-A exit (red) has a somewhat more restricted sight line.  He or she would have less time to react to a pedestrian or bicyclist traveling down the sidewalk.

Just to put some numbers on that, for a Prius with front bumper just crossing the sidewalk, at the Chick-fil-A exit, the head of a 5’6″ person walking at the near edge of the sidewalk would start to become visible approximately 7.5′ before that person entered the driveway.  (That counts the 2′ planting strip there as not being part of the driveway).  At walking speed (3 MPH), the driver would have 1.7 seconds between the time the pedestrian’s head first became visible and the time that pedestrian was in the driveway.  If that person (again at 5’6″ head height) were bicycling at 6 MPH, the driver would have less than a second to reactThat’s less than what is typically cited as an alert driver’s reaction time, which is pretty much the definition of a dangerous situation.

And, as anyone who walks on Maple can tell you, that driver’s eyes are going to be focused on the oncoming traffic.  Waiting to floor it if they seen an opening in traffic.  They will not be looking down the street, for some potential pedestrian or bicyclist on the sidewalk.  I.e., they will be focused on the opposite direction from where the at-risk pedestrian will be coming from.

On top of that, realize the following.

In all likelihood, nobody checked the sight lines in that direction — looking toward Vienna, from the Chick-fil-A-car-wash.  I have been informed, from someone I consider to be a reliable source, that sight lines are checked for cars only.  I.e., can Vehicle 1 see Vehicle 2, and vice-versa.  And, as I understand it, they don’t do checks for sight lines between cars and pedestrians.  So, because Maple is one-way at that point, no one would have done any sight line checks looking toward Vienna.

The new HAWK light means that Madison students can and do use that sidewalk.  Depending on how you hit the light at Nutley, that route via the HAWK light is faster than waiting for the walk sign at Nutley.

That Chick-fil-A exit is likely to be quite busy.  My wife informs me that the drive-through line at the Fairfax Circle Chick-fil-A often circles the building and spills out into Fairfax Circle.  And Chick-fil-A prides itself on getting cars through their drive-through as fast as possible.

When I stir all that together, I come up with the following.

The Town almost certainly didn’t anticipate that transformer being there.  For sure, it does not fit with the whole MAC-is-beautiful vibe.  The Town probably did not check the site lines looking down Maple toward Vienna, because Maple is one way at that point and they only check car-to-car sight lines.  And now that’s going to be a busy entrance, with school kids constituting at least some of the flow past that entrance.

Perhaps the Town should do something proactively here.  For one, they could install a convex mirror, as is typically done at blind corners of this sort.  This would allow drivers to look for pedestrians/bicyclists approaching from the blind side of that entrance.  For another, they could put a bicycle stop sign/stop bar on the sidewalk, or other similar warning device, on the sidewalk, where those transformers are.  That would warn bicyclists and pedestrians to proceed slowly due to the limited sight lines.