Real-world, on-road measurements of physiological stress measured in the field as cyclists travel across different types of bicycle facilities. Presenter: Miguel Figliozzi

1. Measuring Stress Levels for
Real-World, On-Road Cyclists
Presenter: Miguel Figliozzi
Professor of Civil and Environmental Engineering
Oregon Active Transportation Summit
Monday, March 14th, 2016
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2. Motivation
• Recent interest to study cyclists’ levels of traffic
stress, e.g. Furth and Mekuria 2013.
• Several other “stress” or “comfort” measures
• None based on real-world on-road stress
measurements
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3. Background
2010 HCM estimates the performance of facilities
from users that rated video clips filmed from a
bicycle.
GPS data from real-world bicycle trips showed that
cyclists are willing to travel longer distances to
achieve higher levels of safety.
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4. How can we measure real-world on-
road stress ?
Not so easy…
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5. The term “stress” can be defined as a “the
non-specific mix of physiological and
psychological responses of the body to any
demand of change” (Sesyle, 1956)
It is a reaction from a calm state to an excited
state, the subject feels (or thinks that is)
threatened or in danger.
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STRESS

6. Stressful events can cause changes in:
- the autonomic nervous system (ANS), and
- an increase in the sympathetic nervous system
(SNS) activity, and/or
- a decrease in the parasympathetic nervous
system (PNS) activity
Stress can be evidenced by changes in heart rate,
blood pressure, breathing rate, and galvanic skin
response (GSR).
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Stress Measurement

7. Many ingredients…
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Smartphone
GSR sensor
Cameras
Heart rate sensor
Awesome
volunteer !
Power meter

8. Galvanic Skin Response (GSR)
GSR has been utilized by many research studies
in fields ranging from psychology to sports
medicine.
GSR is a robust non-invasive way to measure
stress.
The resistance of the skin changes with the
activity of the sweat gland and small changes in
resistance that can be measured accurately.
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9. Facility types: mixed traffic, off-street,
wide bike lane, and standard bike lane
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4
5
6
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46
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2
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Engineering
Building

10. Bicycle Facilities
Shared roadway
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Bike lane

11. Bicycle Facilities
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Multi-use path I: Waterfront
Park
Multi-use path II: Hawthorne bridge,
Eastbank esplanade, Steel Bridge

12. Data Collection
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• Same route repeated several times
–Peak and off-peak
• Different subjects

13. Measuring stress levels for real-
world on-road cyclists: do bicycle
facilities, intersections, and traffic
levels affect cyclists’ stress?
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14. Does peak traffic impact stress levels? YES
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Low stress High stress
Stress levels during peak-hour traffic were on average 1.75 times higher

15. 15
Do intersections impact stress levels? YES
0
0.2
0.4
0.6
0.8
1
1.2
Intersections Segments
GSRratio
Peak Off Peak

16. What about facility types?
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Multi-use path I: Waterfront park (westside)
Multi-use path II: Eastbank esplanade (more eastside)
0
0.2
0.4
0.6
0.8
1
1.2
Shared roadway Bike Lane Multi-use path I Multi-use path II
GSRratio
Peak Off Peak

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What else can we learn?
A lot, video analysis of peaks and lows…

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GSR curves

19. Video Analysis
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Bus suddenly appeared
almost blocking the lane
(route 68 bus stop)

20. Video Analysis
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Biking along bike lane and
pedestrian crossed the
street blocking path

21. Video Analysis
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The driver opening car
door car next to the bike
lane (put a stroller in
the edge of the bike
lane).

22. Video Analysis
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Pavement
quality is poor.

23. Video Analysis
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Car turning left
and blocking the
path of the cyclist

24. Other issues
• Intersection with high car volume, rider had
to wait until the cars in front turn left or
right.
• The rider was crossing an intersection but
indication turned yellow and had to ride
faster.
• The rider did not cross the intersection on
time and waited on crosswalk (interfering
with pedestrians crossing).
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25. Other issues
• Rider was turning left and was blocked by a
car starting to park
• Rider got confused and missed a turn
• High traffic volumes, vehicles close to cyclist
• Pedestrians or other cyclists blocking or
getting too close
• … and so on…
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26. The term “stress” can be defined as a “the
non-specific mix of physiological and
psychological responses of the body to any
demand of change” (Sesyle, 1956)
It is a reaction from a calm state to an excited
state, the subject feels (or thinks that is)
threatened or in danger.
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STRESS

27. Does peak traffic impact stress levels? YES
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Low stress High stress
Stress levels during peak-hour traffic were on average 1.75 times higher

28. Stressful transition
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29. Another transition with high turning
volumes
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30. Final comments
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Early work but results are very promising
Very specific stress measurements for a
facility, e.g.
- compare segments or intersections
- before/after improvements

31. Collaborators
Modeling and measuring real-world on-road Stress
Alvaro Caviedes (*)
Robin Murray (**)
Hoang Le (**)
Feng Liu (**)
Wu-chi Feng (**)
(*) Department of Civil and Environmental Engineering, PSU
(**) Department of Computer Science, PSU
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32. ORcycle Project
Smartphone app to collect cyclists data
Available for iOS and Android
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33. Safety reports & AskODOT
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Since Nov. 2015 users can email safety reports to
ODOT using the app
- AskODOT receives the email with safety report
data and a link to google maps
- Plus photos and comments
- Commitment to respond within 5 business days

34. Final comments
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Data complementarities
- Orcycle: general policy insights:
- revealed data + questions
- GSR: very specific stress measurements for
a facility, e.g.
- compare segments or intersections
- before/after

35. Learn more… Related Papers and Reports
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1. Blanc, B., & Figliozzi, M. (2016a). Modeling the Impacts of Facility Type, Trip
Characteristics, and Trip Stressors on Cyclists’ Comfort Levels Utilizing
Crowdsourced Data. Forthcoming 2016 Transportation Research Record.
2. Blanc, B., Figliozzi, M, Clifton, K. (2016b). How Representative of Bicycling
Populations are Smartphone Application Surveys of Travel Behavior,
Forthcoming 2016 Transportation Research Record
3. Figliozzi, M.A., (2015). Evaluating the use of crowdsourcing as a data
collection method for bicycle performance measures and identification of
facility improvement needs, Final Report SPR 768, ODOT,
http://www.oregon.gov/ODOT/TD/TP_RES/pages/researchreports.aspx
4. Caviedes, A. & Figliozzi, M. (2016) Measuring stress levels for real-world on-
road cyclists: do bicycle facilities, intersections, and traffic levels affect
cyclists’ stress? Presented at 2016 Transportation Research Board Annual
Meeting, Washington DC.
5. More papers under review…

36. Learn more…
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About the projects
http://www.pdx.edu/transportation-lab/orcycle
Download the app, for iOS or Android
Search “ORcycle” in the iTunes App Store or in
Google Play
Send safety reports to AskODOT using ORcycle
Email us at: ttplab@pdx.edu

37. THANK YOU
Questions? Comments…
Visit our webpage :
http://www.pdx.edu/transportation-lab
Email us at: ttplab@pdx.edu
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