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LED ROADWAY LIGHTING. Presented by Amin Salman/t.d.o.t. Lighting the roads. Roadway lighting is a proven safety countermeasure. The positive safety effects of lighting have been documented in various reports and publications. Source: FHWA Lighting Handbook August 2012.
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LED ROADWAY LIGHTING Presented by Amin Salman/t.d.o.t
Lighting the roads • Roadway lighting is a proven safety countermeasure. The positive safety effects of lighting have been documented in various reports and publications. Source: FHWA Lighting Handbook August 2012. • HID is the technology of the 60s and LED is the future.
Us Department of energy • Of the numerous illumination platforms currently available, only Solid State • Lighting-in the form of Light Emitting Diodes (LED)-offers our nation the • potential to save energy and enhance the quality of our environment.
LED benefits LED Benefits: - Decreased energy consumption & costs - Reduced maintenance costs; due to longer life - Visible commitments to efficiency - Improved safety through enhanced visibility - Decreased light trespassing and pollution - No mercury, lead, or other known hazards -Programmable controls/Dimming
Disadvantages of led • Expensive initial cost …(but better life-cycle cost) • Performance largely depends on ambient temperature & heat-sinking (you can’t just stick an LED in a regular fixture housing) • Light loss factors (LLFs) are not easily determined • Must be supplied with the correct current (needs a power supply/driver to convert AC to DC) • Because of their long life, they may not undergo the routine cleaning every 3-5 years typically corresponding with re-lamping.
Luminaire efficiency TYPICAL 150 WATT HIGH PRESSURE SODIUM STREET LIGHT MEASUREMENT OF LUMENS REACHING THE GROUND • TOTAL LUMEN OUTPUT OF HPS LAMP 22000lm 100% • DOWNWARD STREET SIDE 6656lm 30.3% • DOWNWARD HOUSE SIDE 6057lm 27.5% • DOWNWARD TOTAL LUMENS 12712lm 57.8% • REFLECTOR INEFFICIENCY -9278lm 42.2%
Pedestrians • 5,376 were killed and approximately 70,000 injured in motor vehicle crashes on public roadways in the U.S in 2015. Pedestrians comprised about 15% of crash deaths. 12% of pedestrians were injured in a non-roadway location such as parking lot and therefore wouldn’t be counted in police-reported crash statistics (meaning it’s more than 70,000). Source: Insurance Institute for Highway Safety and Highway Loss Data Institute.
Locations of Pedestrians crashes • 54% of pedestrian deaths occurred in major roads and specifically at intersections (26%). Among pedestrian crashes of all severities, the most common scenario involves pedestrians crossing in front of a passenger vehicle that is traveling straight. These crashes typically occur on roads with speed limits below 40 mph, and about half occur at intersections.
How to improve pedestrian safety? • Three main approaches: • Separating pedestrians from vehicles by time or space; • Making pedestrians easier to spot; • And reducing vehicle speeds.
Using Led for Intersection Lighting • Contrast, is strongly correlated with quick identification of pedestrians and night-time crash reduction. • Higher vertical illumination results in better visibility in the cross walk.
LED in Tennessee -The City of Knoxville: Largest LED Street Light Project in the State. Replacing: 29000 HPS/MV to LED. Final Cost: $13 million. Annual Energy Saving: $1,054,364. -AUB (Athens Utility Board): Complete conversion to LED by January 2017.(E-mail dated 4-10-17 from Alexa Voytek-Program Manager at TDEC) -Jim Kerr-Murfreesboro City-sent an e-mail to use LED lights for SR-268 (Thompson Lane): From Broad St. to Memorial Blvd -TDOT First Project: Interchange I-40 & SR-171 Mt. Juliet, Wilson Co.
Led standards and specifications • Will be included in the updated version of TDOT Standard Specifications for Road and Bridge Construction (hopefully the 2018 Edition) & Traffic Operations Manual.