New Approaches to Lighting for Safety and Sense of ...€¦ · New Approaches to Lighting for Pedestrian Safety and Sense of Personal Security John D. Bullough Lighting Research Center,

© 2017 Rensselaer Polytechnic Institute. All rights reserved.

New Approaches to Lighting for Pedestrian Safety and Sense of

Personal Security

John D. BulloughLighting Research Center, Rensselaer Polytechnic Institute

TRB Human Factors Workshop 149CWalking at Night: The Pedestrian’s Perspective, or “The Dangers of the Night‐Walkers”

January 8, 2017


Workshop Presentation Objectives

Identify new approaches to pedestrian‐friendly lighting Compare different alternatives to conventional overhead street and area lighting Describe the impacts and potential benefits of new types of pedestrian lighting Analyze the visual, perceptual and safety impacts of the geometric and spectral properties of pedestrian lighting

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Background

Pedestrian fatalities were 11% of total vehicle crash fatalities nationwide› In New Jersey, this percentage was 21% (NHTSA, 2006)

RP‐8: Roadway Lighting (IESNA, 2014): › Minimum vertical illuminance (Ev) is 10 lux for high pedestrian conflict

areas with mixed pedestrian‐vehicle use › Minimum vertical illuminance (Ev) is 2 lux for medium pedestrian conflict

Increasing Ev can provide better visibility of pedestrians (Hasson et al., 2002)

10 lux Ev sufficient for pedestrian detection (Gibbons et al., 2006; Edwards et al., 2007)

But is an Ev of ~10 lux all that we need to know?

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LRC’s Approach to the Problem

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Photometric simulations

Visual performance analyses

Outdoor visibility experiment

Develop performance specifications

Real‐world evaluations

© 2017 Rensselaer Polytechnic Institute. All rights reserved.5

Relative Visual Performance

The Relative Visual Performance (RVP) model (Rea and Ouellette, 1991) is a quantitative model based on speed and accuracy of visual processing

RVP value is a function of background luminance, luminance contrast and visual size

Excellent visibility can be obtained when RVP>0.9 (Rea, 1986)

increasing background luminance


RVP: Plateau and Escarpment

Once high visual performance is achieved, further increases in light level do not improve visibility

(Rea and Ouellette, 1991)

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RVP and Light Levels

Higher Ev does not always provide better visibility (e.g., pedestrian in black [ρ=10%], size=2 ft5 ft, background luminance [Lb]=1 cd/m²):

40 year old driver, 100 ft awayEv=11 lux Contrast=‐0.65 RVP=0.96Ev=30 lux Contrast=‐0.05 RVP=0.17

RVP value is used as an evaluation criterion for evaluating different crosswalk lighting designs

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Applications of the RVP Model

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Highway Sign Legibility Roundabout Hazard Detection

Headlight Pedestrian Identification Distance Intersection Nighttime Crash Frequency

(Bullough and Radetsky 2014)

(Schnell et al. 2009) (Bullough and Skinner 2012)

(Bullough and Skinner 2009) (Bullough et al. 2013)


Conventional Overhead Lighting

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Overhead Lighting Set 15 ft. Ahead

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Bollard‐Based Lighting

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Visual Performance Evaluation Summary

Overhead lighting at the crosswalk location can result in reduced contrast of pedestrians or areas of transition between “negative” and “positive” contrast

Bollard‐level luminaires providing vertical illumination maintain “positive” contrast, without competing against vehicle headlights

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Outdoor Visibility Experiment

A: Headlights onlyB

C

D

In-kind support:The Lighting Quotient


Results: Outdoor Visibility Experiment

A: Headlights onlyB

C

D


Performance Specification

• ≥10 lux vertical illuminance @ 3 ft. above ground within the crosswalk

• ≤1 lux vertical illuminance @ 5 ft. above ground to minimize glare

• “White” light to enhance brightness and contrast with existing overhead high pressure sodium illumination (stay tuned!)

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Field Demonstration – Old Bridge, New Jersey Exterior floodlight luminaires were

modified to create bollard fixtures U.S. Route 9 and Texas Road, Old Bridge,

Middlesex County, NJ Participation from individuals from NJDOT,

NJ Transit, Old Bridge Police Department

Sponsor: New Jersey Department of Transportation In‐Kind Support: Philips Hadco 16


Field Demonstration – Slingerlands, New York At roundabouts, pedestrian crosswalks appear in unexpected

locations, and conventional overhead lighting does not enhance contrast of pedestrians

LRC installed bollard‐based crosswalk lighting in conjunction with landscape and low‐level overhead “ecoluminance” lighting – 75% energy use reduction

Sponsor: New York State Department of Transportation, In‐Kind Support: Forms + SurfacesNew York State Energy Research and

Development Authority 17


Field Demonstration – Aspen, Colorado Prototype light‐emitting diode

(LED) luminaires designed to meet the LRC’s performance specification were installed in a temporary demonstration in Aspen, Colorado

Observations by city engineering staff and survey questionnaires of residents and tourists were very positive

Sponsor: City of Aspen In‐Kind Support: 3M, Intrigue Lighting

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Field Demonstration – Aspen, Colorado

Sponsor: City of Aspen In‐Kind Support: 3M, Intrigue Lighting19


Field Demonstration – Schenectady, New York Crosswalk bollard luminaires were

modified to produce low intensity (<1 lux) in crosswalk until activated by push button

Upon activation, luminaires produce three cycles of high and low intensity to serve as an alerting effect

Installed luminaires in Schenectady, NY were judged favorably by observers from the city, Metroplex development authority, and by members of the public

Sponsor: University Transportation Research Center In‐Kind Support: 3M, Intrigue LightingMetroplex Authority

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Visit Poster 17‐00475 (Board N479)in Session 659!


Field Demonstration – Schenectady, New York

Sponsor: University Transportation Research Center In‐Kind Support: 3M, Intrigue LightingMetroplex Authority

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Summary: Lighting for Crosswalks Bollard‐based lighting system

for crosswalks was judged to be promising for improving pedestrian safety

Found to be practical and acceptable by transportation, transit and public safety professionals

› Field tested in New Jersey, New York, Colorado› With optical (and temporal) control, glare from luminaires is minimized

Visual performance analysis is a practical safety‐related evaluation tool

Featured in transportation lighting guidance from Transportation Research Board, Minnesota Department of Transportation

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Can Light Source Color Impact Perceptions of Personal Security?

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Locations that appear brighter tend to be judged as safer(Rea et al. 2009)

∴ Scene brightnesscan be used as a lighting metric for personal

security

scenebrightness

personalsecurity

79%

66%

High Pressure Sodium (HPS)

Metal Halide (MH)

To be judged equally bright, the MH

illuminance was 79% of the HPS illuminance(Rea et al. 2009)


HPS vs. Metal Halide (MH)

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Empirical results: 79% Theoretical model: 79%

scenebrightness


HPS vs. MH vs. LED in Three Parking Lots

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Safety ratings were highly correlated with brightness quantities, rather than

conventional illuminance quantities

(Rea et al. in press)

(ave. 46 lux) (ave. 6 lux)

(ave. 15 lux)


Summary: Light Source Color/Spectrum

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Tuning the spectral/color content of roadway and outdoor lighting can result in differences in perceived brightness› These in turn influence

perceptions of safety and personal security

May provide opportunities to reduce energy use, light pollution, when pedestrian perceptions are important

https://cms.dot.gov/utc/maximizing‐pedestrians‐perceptions‐safety‐using‐light‐source‐spectrum


Acknowledgments

New Jersey Department of TransportationNew York State Department of TransportationNew York State Energy Research and Development AuthorityCity of Aspen, ColoradoUniversity Transportation Research Center – Region 2Philips LightingThe Lighting QuotientTown of Bethlehem, New YorkForms + Surfaces3MIntrigue LightingSchenectady County Metroplex Development AuthorityBonneville Power AdministrationUniversity of Washington

Nicholas SkinnerMark ReaXin ZhangJeremy SnyderPatricia RizzoRosa CapóUte BeseneckerYukio AkashiLeora RadetskyJennifer Brons

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Thank you!Questions?

John D. Bullough, [email protected], www.lrc.rpi.edu/safety

New Approaches to Pedestrian Lighting

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Possible Discussion Questions

At which locations is visual performance of primary importance? At which locations are perceptions of safety/security of primary importance?

What other lighting techniques would maximize positive contrast of pedestrians?

Could a performance specification for lighting based on visual performance be practical?

What further research is needed to validate the visual performance model?

Is there an “objective” way to measure perceptions of safety/security?

New Approaches to Lighting for Safety and Sense of ...€¦ · New Approaches to Lighting for Pedestrian Safety and Sense of Personal Security John D. Bullough Lighting Research Center,

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