San Jose Story

CONTACT INFORMATION:Nancy Clanton, PE, FIES, IALD, LC, LEED AP

PresidentClanton & Associates, Inc.

4699 Nautilus Court South, Suite 102Boulder, CO 80301

303-530-7229Nancy@Clantonassociates.com

New Exterior Lighting Design Issues

Luminance (STV)

AdaptationContrastUniformity

Glare

Adaptive StandardsSpectral Effects

Illuminance –Intersections only

Traditional StreetlightingHPS and LPS

• Poor color rendering• Traffic Signal Confusion• Energy Efficient (?)• Medium Maintenance

(lamp replacement every 4 years)• Harder to dim• Cheap first cost• LPS monochromatic – Lick

Observatory

Research Questions• Which light source is preferred by the community?• Is there a visibility enhancement with broad spectrum (white)

light sources?– Detection distances– Color contrast

• Can lighting levels be reduced (50%) and still achieve safety goals?

• What is the difference in energy use?

Subjective Evaluation1. ‘It would be safe to walk here, alone, during daylight hours’2. ‘It would be safe to walk here, alone, during darkness hours’3. ‘The lighting is comfortable’4. ‘There is too much light on the street’5. ‘There is not enough light on the street’6. ‘The light is uneven (patchy)’7. ‘The light sources are glaring’8. ‘It would be safe to walk on the sidewalk here, alone, during darkness

hours’9. ‘I cannot tell the colors of things due to the lighting’10. ‘The lighting permits safe navigation.’11. ‘I like the color of the light.’12. ‘I would like this style lighting on my city streets.’13. ‘How does the lighting in this area compare with the lighting of similar

city streets at night?’

Visibility Tests

•Objective assessment of small target visibility•Response metric (object detection distance)•Illuminance and luminance metrics (meters mounted on the car)

Experimental Vehicle with RLMMS Components

San Jose: Targets

San Jose Streetlight Demonstration & Testing

• Full power night 1 (wet pavement)

• 50% power night 2 (dry pavement)

• 6 types of lights: HPS, LPS, Induction & 3 LED

Color Temperatures Tested

Sought to test different Kelvin temperatures to see if it made difference in detection distances

LED 3500K

LED 4000K*

LED 5000K

Induction 4000K*

Demonstration Site on Hellyer Road

INDUCTION 4KHPS

LED 5K

LED 4K

LED 3.5K

LPS

Findings: Subjective Evaluation

Public preferred the White Light Options

Warmer looking white light options were preferred

Even at half the lighting level, people felt there was enough light

Public did not like LPS or HPS

San Jose – Detection distance vs watts per linear feetHIGH (100%) setting

San Jose – Detection distance vs watts per linear feet

LOW (50%) setting

Implications for Lick Observatory

Predicted Spectral Power Distributions

San Jose Findings

• Broad Spectrum (White) Light– Prefer white light– See as far if not further than HPS/LPS

• Dimming– At 50%, most thought light sufficient– At 50%, minor reduction in detection

distance

Public did not like LPS or HPS

Centralized Controls –

Dimming strategies include• Curfew• Occupancy controls• Peak load dimming• Demand response

Two way communication

Outdoor Lighting Operation Status

Virtual Metering (good for adaptive standards)

Warranty Support

Energy Savings ProjectionsFull Power Only = 16% to 44%Full and Half Power = 33% to 64%

Streetlighting Guidelines

Streetlighting Guidelines Adaptive Standards

San Jose (collector – high ped)

• Replace 180w LPS with 150w LED

• 4000K • Dim lighting by 50%

during low pedestrian activity

Next Study ---Visual Performance and Community Acceptance of LED

Streetlight Sources• Wet and Dry Pavement• Illuminance and Luminance based set-up• Luminaires from one manufacturer• Asymmetric and symmetric distribution

Questions?