Measuring Stress Levels for Real-World, On-Road Cyclists

Presenter: Miguel Figliozzi Professor of Civil and Environmental Engineering

Oregon Active Transportation SummitMonday, March 14th, 2016

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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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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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How can we measure real-world on-road stress ?

Not so easy…

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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

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

Many ingredients…

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SmartphoneGSR sensor

CamerasHeart rate sensor

Awesome volunteer !

Power meter

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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Facility types: mixed traffic, off-street, wide bike lane, and standard bike lane

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EngineeringBuilding

Bicycle FacilitiesShared roadway

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Bike lane

Bicycle Facilities

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Multi-use path I: WaterfrontPark

Multi-use path II: Hawthorne bridge, Eastbank esplanade, Steel Bridge

Data Collection

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• Same route repeated several times–Peak and off-peak

• Different subjects

Measuring stress levels for real-world on-road cyclists: do bicycle facilities, intersections, and traffic

levels affect cyclists’ stress?

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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

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Do intersections impact stress levels? YES

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Intersections Segments

GSR

ratio

Peak Off Peak

What about facility types?

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Multi-use path I: Waterfront park (westside)Multi-use path II: Eastbank esplanade (more eastside)

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Shared roadway Bike Lane Multi-use path I Multi-use path II

GSR

ratio

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

Video Analysis

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Bus suddenly appeared almost blocking the lane(route 68 bus stop)

Video Analysis

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Biking along bike lane and pedestrian crossed the street blocking path

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).

Video Analysis

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Pavement quality is poor.

Video Analysis

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Car turning left and blocking the path of the cyclist

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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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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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

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

Stressful transition

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Another transition with high turning volumes

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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

CollaboratorsModeling 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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ORcycle Project

� Smartphone app to collect cyclists data

� Available for iOS and Android

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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

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

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…

Learn more…

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About the projectshttp://www.pdx.edu/transportation-lab/orcycle

Download the app, for iOS or AndroidSearch “ORcycle” in the iTunes App Store or in Google Play

Send safety reports to AskODOT using ORcycle

Email us at: ttplab@pdx.edu

THANK YOU Questions? Comments…

Visit our webpage :

http://www.pdx.edu/transportation-lab

Email us at: ttplab@pdx.edu

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