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Cool link, thanks!

The Level 2 chargers supply 240 volts and typically provide up to 20 miles of range for every hour you’re plugged in.
Oh if only the Volt/ELR could add 20 miles per hour. Someday maybe the Volt will get 6.6 or 7.2 KW charging capacity, after GM wakes up to the desire for opportunity charging. If ever.
 

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interesting read, thanks for posting.
 

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For same light output on ground, I don't know that LED is lower cost (or power) than HPS, I imagine they are giving up something in their exchange.
 

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Streetlights for Collector Roads

Abstract

The National Lighting Product Information Program (NLPIP) at Rensselaer Polytechnic Institute's Lighting Research Center (LRC) purchased 14 streetlights, identified by a specifier survey, between July and October 2009. Four used high pressure sodium (HPS), one used induction, eight used light-emitting diodes (LEDs), and one used pulse-start metal halide (PSMH) light sources. NLPIP determined how many of each type of streetlight were needed to illuminate 1.0 mile (1.6 kilometer [km]) of a collector roadway to meet the design criteria specified by the American National Standards Institute (ANSI)/Illuminating Engineering Society of North America (IESNA) RP-8-00 (R2005), the American National Standard Practice for Roadway Lighting (referred to as RP-8 below). NLPIP then calculated power demand and costs per mile.

NLPIP found that:

On average, the LED streetlights and the induction streetlight could be spaced only about one half the distance of the HPS and PSMH streetlights and still meet the RP-8 lighting criteria. If an HPS or PSMH streetlight system just meeting RP-8 is replaced with the LED or induction streetlights tested in this report on a one-for-one basis, the streetlight system will not meet RP-8.
The life cycle cost per mile is dominated by the initial and installation cost of the poles, not the initial cost of streetlights or any potential energy or maintenance cost savings. Because of the narrower pole spacing required to meet RP-8, the life cycle cost of the LED streetlights tested for this study is up to twice that of the HPS and PSMH streetlights tested.
On average, the LED streetlights require 1% and 10% less power per mile than the HPS streetlights tested in staggered and single-sided layouts, respectively. On average, the LED streetlights require 8% and 24% less power than the PSMH streetlight tested in single-sided and staggered layouts, respectively.
The street-side lumens metric is a useful parameter for comparing streetlight layout costs.
At the illuminance levels typical of collector roadways, power requirements for "white light" sources are 3% to 19% lower than HPS sources based on models of mesopic photometry.
http://www.lrc.rpi.edu/nlpip/publicationDetails.asp?id=927&type=1
 

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For same light output on ground, I don't know that LED is lower cost (or power) than HPS, I imagine they are giving up something in their exchange.
Yes, range of light.
LED streetlamps are generally flat and pointing downward with a very even coverage pattern.
Less leaking light up (=light pollution) and more effective use of light = more efficient use of power.
Thus, significantly less watts for the same ground coverage, even though LEDs aren't immensely more efficient than HPS.

They've replaced them all here, and the new ones are leaps and bounds better in both illumination and visibility (white means you can actually see vs just a disgusting yellowish shadowy object) all while using less power.
 

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For same light output on ground, I don't know that LED is lower cost (or power) than HPS, I imagine they are giving up something in their exchange.
Lighting is my profession. Today's LED street light fixtures still cost more for similar target light output but not that much anymore. Power and maintenance are less and can cost significantly less for LED's depending on rates. Payback is good unless you assign no value to maintenance. That said, it only frees up about 50-150W of capacity per fixture when replacing 150-400W HPS lamps unless lower light levels are acceptable. Existing power would have to be substantially over designed or you could only have one charger per every 10 fixtures or so best case to achieve a Volt-like charge rate (~40 miles per night).
 

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Yes, range of light.
LED streetlamps are generally flat and pointing downward with a very even coverage pattern.
Less leaking light up (=light pollution) and more effective use of light = more efficient use of power.
Thus, significantly less watts for the same ground coverage, even though LEDs aren't immensely more efficient than HPS.

They've replaced them all here, and the new ones are leaps and bounds better in both illumination and visibility (white means you can actually see vs just a disgusting yellowish shadowy object) all while using less power.
This organization (https://astronomynow.com/2015/08/12/iss-astronaut-pictures-of-earth-used-for-light-pollution-studies/) disagrees with your statement that LEDs have less light pollution. In fact they say:

"LED streetlights have been installed or announced for installation in several large cities as well as smaller cities throughout the world. LED street lights actually make light pollution — such as sky glow — significantly worse, as they emit more blue and green light than the high-pressure sodium lights that they typically replace."

Because of how the sensitivity of the human eye varies with frequency, perceived brightness may compensate for reduced lumens when replacing low pressure sodium street lights with LEDs, allowing us to see better with LED lighting.

If quality of the circuitry components were on a par with the LEDs, payback is better than with current street lighting, as KOZ points out. However, if all of the non-functioning LEDs we see in traffic lights is the yardstick by which payback is measured, I would hesitate to agree with him on that point. AFRAK, LEDs themselves rarely fail. Material contamination has been under control for many years now. Resistors and capacitors, on the other hand, do vary in quality.

That said, anything that increases our ability to see when driving at night is a boon.
 

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Can't speak to all models of street lights, but I can speak to the ones they used here - that night time sky glow is significantly reduced in my neighbourhood/town since they switched.
The old lamps were probably especially bad at aiming downward, had too many lumens, or a combination of both. Can't comment for sure as I'm not a lighting expert. But to my untrained eye, it's noticeably less.
 
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