Penn potomac independent audit - karen lin

Pedestrian Behavior &
Artifact Audit
June 2013
An Independent Review for the
Penn-Potomac Avenue SE Pedestrian Safety Study
Karen T. Lin
Human Factors & Public Safety Consultant
karen.t.lin@gmail.com | +1 435 565 4544 | karentl.com

INTRODUCTION
My name is Karen T. Lin and I’m an independent human
factors consultant. As a new DC area resident who walks
around the Penn-Potomac neighborhood, I am volunteering
my services pro bono for the benefit of the Penn-Potomac
Avenue SE Intersection Pedestrian Safety Study and for the
benefit of the public for which it affects.
I’ve conducted a high-level behavior audit of the immediate
intersection and would like to share my initial findings and
human-centered design recommendations with any and all
parties committed to the pedestrian safety study.
2June 2013 This is an independent audit © 2013 Karen T. Lin

APPROACH
Human factors is the field of study concerned with the
human-centered design of a system, service or product to
reduce error and other undesired outcomes while
optimizing for desired outcomes in human and system
performance.
In this This is an independent audit, I visited the Penn-
Potomac intersection to observe pedestrian behaviors and
record artifacts (observable signs of human or system
activity) and identify trends or patterns that are creating
undesirable conditions for pedestrian safety today.

Walking paths between Metro and major bus stop
B
Paths via marked pedestrian walkways
Paths via shortest walkable distance
Barriers to walk around (fences, bus stop stands)
M
M B
4June 2013 This is an This is an independent audit © 2013 Karen T. Lin

A closer look at the “spread” of the foot paths
The “spread” suggests pedestrians may be crossing through from different angles
and/or treading the sidelines while waiting to cross traffic.
5June 2013 This is an This is an independent audit © 2013 Karen T. Lin

PHOTO OF FOOT PATHS & SPREADS: View from main bus stop to the Metro station. Again, the
“spreads” indicate pedestrians may be treading along the curblines and/or jaywalking diagonally to
cross the streets, presumable to weave between cars & buses.

The Southwest Corner = More foot paths and problems
Seen and unseen footpaths School crossing guard station
Mon-Fri 7:00-9:00am & Mon-Thu 2:00-4:00pm, Fri 12:00-2:00pm
Triangular median

PHOTOS: Views of the other foot spreads and paths. Notice there are NO physical
barriers to prevent pedestrian from taking shortcuts into traffic.
Foot spread outside the Penn
Ave outbound bus stop
Foot path/spread at Penn-
Potomac going southbound

PHOTO: View of the triangle median and its pedestrian walkway. Notice how the “stop
for pedestrians” sign is facing at an angle AWAY FROM cars driving into the walkway…

…and instead, the sign faces pedestrians on the foot path. This may give pedestrians a
false sense of security to see this sign while the drivers don’t see it.

OPPOSITE VIEW: A Garda truck parks here often, blocking the path and view of cars
turning right from Penn Ave. (Note lack of road markings to indicate proper use of lanes.)

OTHER ISSUES: Who is this walk sign for?
This walk
signal is
missing a
corresponding
crosswalk.
All other walk
signals in this
area have
corresponding
crosswalks.
Side note:
Again, it’s
unclear if
there are one
or two lanes.
Cars squeeze
in to not get
stuck or
backed up on
the turns.

OTHER ISSUES: Misleading “allowance” of shortcuts
The wrought-iron fence (right) ends in a “misleading” way. People with wheelchairs & strollers
cross over to the Metro station, only to find no ramp or walkway. (I witnessed a man in a powered
wheelchair attempt to navigate onto the road WITH traffic to get around the curb.)

ADDITIONAL CONSIDERATIONS
Pedestrian STOP signs should face oncoming traffic in the
order of the driver’s viewing angle. Especially in cases of
curving roads, pedestrian stop signs must precede the
walkway in order of the driver’s attention events.
1. Driver’s viewing angle
changes with the road, sweeping
RIGHT TO LEFT in this example.
2. Therefore, place the sign to the
right of the walkway, facing the angle
at a safe distance in before driver sees
and enters the walkway
3. For a road bending right, the
driver’s view sweeps from LEFT TO
RIGHT, so the sign should be placed
on the left of the walkway.

Use pedestrian barriers to discourage accidents. In cases
where jaywalking pedestrians must check for car traffic
over their shoulder and from multiple directions, use
barriers (no more than 4 feet tall) along medians to
discourage the behavior.
car traffic
car traffic
foot traffic to
prevent with
barriers

Use road markings to clarify usage. Where roads are
physically wide enough for two lanes but are unmarked, it
creates driver confusion and ambiguity on appropriate
usage – and adds risk in high traffic hours.
Example 1: Dotted white line to
indicate two lanes.
Example 2: Straight white lines as
margins for a single lane of traffic.

ADDITIONAL NOTES
• School crossing guard mentioned several other safety
concerns regarding parents with cars dropping children
off in unsafe zones, students themselves not using her
crosswalk (or any crosswalks), cars that drive by too
quickly, and needing more crossing guards (as she is the
only one).
• The wrought-iron fence is mostly camouflaged by
bushes. I witnessed at least 2 people attempt to cross
between the bushes only to realize they would have to
walk around it. Bushes/plants should be maintained at a
shorter height to discourage shortcut attempts.

THANK YOU
I’m happy to assist anytime with questions, concerns,
and/or if I may be of any additional help.
Karen T. Lin
Human Factors & Public Safety Consultant
karen.t.lin@gmail.com | +1 435 565 4544 | karentl.com

Penn potomac independent audit - karen lin

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