The City of Las Vegas is replacing all their streetlights with LED.

Here is an excerpt from the Road Warrior column in today's Las Vegas Review-Journal:

"The greatest benefit of LED is the uniformity of the light distribution. The old HPS, or "yellow" lighting, would create city blocks of "bright, dim; bright, dim; bright, dim," Uniformity is as important as intensity, especially when it comes to drivers being aware of pedestrians or other things that sometimes we all find in the street.

In addition to uniformity, LED lighting results in greater color rendering - or the ability to see a color as close to its true shade as possible. Pedestrians dressed not only in black, but blue, brown, green and even red, can be more difficult to discern with HPS lighting than with LED, which Rohleder says has a color rendering of up to 90 percent, making pedestrians more visible to drivers.

(What came to my mind is that witnesses will have an easier time identifying the colors of the hit-and-run cars - it's open season on pedestrians in Las Vegas the past couple of years.)

A side benefit to replacing the old HPS lights in neighborhoods is that many homeowners found them intrusive, with their yucky yellowness burning figurative holes into their backyard serenity, or glaring unwanted into their homes while they watched TV. But there are some folks, Rohleder notes, who miss the HPS lights because they provided free "security lighting" to parts of their property.



"The biggest complaint we've had - and overwhelmingly complaints have been minimal - has been the initial eeriness of the (LED) lighting. Some people feel at first like they're walking out into a cold, frigid area."

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Looking at some technical information about LED street lighting, there is some discussion of the heat sink. A heat sink is a block of metal with separated layers so there is a lot of surface area to dissipate heat. A very common use of them is inside computers.



The highest average overnight low temperature in Las Vegas is 78 degrees in August (average high is 104, but we've seen it get to 110 and higher), so I hope these new lights can handle it. I looked at a list of cities currently using LED, and Mesa, Arizona (right next to hot, hot Phoenix) is one of them. Most of the cities are in colder climates, particularly Great Britain.

A kitchen example of a heat sink is for thawing meat. You can use a ribbed grill pan set on the top of your kitchen stove (lots of metal surface): place your pound of wrapped meat on the grill pan, and it'll thaw quickly. When I don't have a grill pan, I use a saucepan or cast iron skillet. You can tell it's working because the pan and stove around it get so cold.