Better Streetlights for Tulsa

[dsjeffries]

Kendall-Whittier's West Park project Acorn Lights:  FAIL

I agree, acorn lights are terrible. But I think they're a little different than most acorn lights we see in this city. A little. When I've been over there at night, it seemed like they had some sort of top shield installed inside the glass. They didn't seem to project light in a 360 degree glare bomb fashion, only 180 degrees. I say "only" partly in jest. It's slightly better, but they still suck as a lighting choice. My only guess is that because TU was involved, GKFF caved on the lighting (even though they have made some fantastic choices in the Brady District) so TU could have continuity in design.

[patric]

I agree, acorn lights are terrible. But I think they're a little different than most acorn lights we see in this city. A little. When I've been over there at night, it seemed like they had some sort of top shield installed inside the glass. They didn't seem to project light in a 360 degree glare bomb fashion, only 180 degrees. I say "only" partly in jest. It's slightly better, but they still suck as a lighting choice. My only guess is that because TU was involved, GKFF caved on the lighting (even though they have made some fantastic choices in the Brady District) so TU could have continuity in design.

Acorn lights (or really any "decorative" lights) become a problem when people try to use them as the primary roadway light source.

Acorn lights were originally designed for much lower intensity Incandescent or gas light, when the design standards called for street illumination to be slightly better than that of the full moon.  It worked because they were supplementing existing illumination, as opposed to dominating.

Illumination standards today are multiples of that, and glare suppression is much more critical.  Where we fail is by exceeding the design limitations of older fixture styles, pumping thousands of lumens through optics that were only designed for a few hundred.
The result is blinding, vision-robbing glare.

I have also seen recent Acorn designs that have tried tricks with internal baffles and computer-designed refractors around town, but they merely soften the blow rather than effectively address the problem (like a filter on a cigarette).

We can have our pretty Acorns and well-lit streets at the same time:  How?  Keep decorative lights at decorative intensities, and use better designed street lights to actually light the streets.

Here's what actual lighting experts recommend; it involves high-mounted shielded (Full-Cutoff Optics) street illumination, in conjunction with reduced-intensity decorative post-top lights (for dayform, and a little pizzazz at night):

[Cetary]

That picture reminds me of this...



Supposedly the lights in the foreground are only running at half the power of the ones in the background. That would reinforce an earlier post saying that you could get a 50 watt sodium bulb to do the work of a 100 watt bulb.

[patric]

That picture reminds me of this...



Supposedly the lights in the foreground are only running at half the power of the ones in the background. That would reinforce an earlier post saying that you could get a 50 watt sodium bulb to do the work of a 100 watt bulb.

...IF you use the newer shielded fixtures that re-direct what would be wasted light, downwards.

That's an interesting shot, because it almost looks as if some of the fixtures arent working, until you look at the lit street below.

[Cetary]

I found something interesting.

http://www.darksky.org/assets/documents/MMPG.pdf

You can see how the conversion to more appropriate light intensities along with upgraded optics help to cut over half the energy use in the boulevard. You can also see how much more discrete the neighborhood lighting is.   

[patric]

I found something interesting.

http://www.darksky.org/assets/documents/MMPG.pdf

You can see how the conversion to more appropriate light intensities along with upgraded optics help to cut over half the energy use in the boulevard. You can also see how much more discrete the neighborhood lighting is.  

A couple things might get in the way of your message;

One, dont lead the charge with a barrage of numbers, but do have them handy to support your position, and
Two, make it relevant to the needs of the community.  
The handout you cited has some useful information, but overall gives the perception of some astronomy special interest that city leaders can easily dismiss.

Glare is a big concern, and very timely.  There have been three deaths in the past two weeks in Tulsa form drivers not being able to see pedestrians.
These didnt happen on dark country roads, but in brightly-lighted areas on primary streets.
In each case, bright, glarey commercial lighting overwhelmed both the street lighting and the motorists headlights.

It was reported that TPD spent two hours investigating the auto-pedestrian death at 51st & Lewis, so I have to wonder if that didnt include identifying sources of glare or maybe doing an Isofootcandle Plot showing a grid of what light is where (but im not holding my breath).

Energy waste is also a big concern -- one that's being addressed by the conversion to LED lighting.  Lets face it, High Pressure Sodium is the workhorse of streetlighting, but it's orange glowing days are numbered (as are outdated and technically flawed "recommendations" from utility companies that streetlights "must be at least 100 watts").  LED conversions can be poorly done, however, when those doing the conversion dont really understand the details of human vision at night.

The goal of street lighting is to light streets in order to improve nighttime visual acuity, public utilization and safety.  
Go from there.

[Cetary]

Alright, I just thought that the document was interesting and was worth sharing.

Now as I understand you can light a neighborhood to federally recommended standards with a 70 watt HPS semi-cutoff. Now, I wanted to know what sort of wattage would you recommend,assuming the lights are HPS full-cutoffs with a pole height of 19 feet and spacing of 125 feet, for this street? It's Shaw Ave. between Palm and Maroa.

http://goo.gl/maps/zzVMu

Also, if the city were to go with warm white LEDs in full-cutoff, around 3000k, what wattage would you recommend then?

[patric]

Now as I understand you can light a neighborhood to federally recommended standards with a 70 watt HPS semi-cutoff. Now, I wanted to know what sort of wattage would you recommend,assuming the lights are HPS full-cutoffs with a pole height of 19 feet and spacing of 125 feet, for this street?
Also, if the city were to go with warm white LEDs in full-cutoff, around 3000k, what wattage would you recommend then?

For starters...
100 Watts incandescent isnt the same as 100 Watts Fluorescent which isnt the same as 100 Watts Sodium which isnt the same as 100 Watts Metal Halide which isnt the same as 100 Watts LED.

For our purpose, light output is measured in Lumens. 
Footcandles is the metric we use to measure Luminance (the light reflected from a lighted surface) or Illuminance (the light radiating from a light source).  Europeans prefer Lux to Footcandles, so you see both terms used in literature.

Watts is a measure of how much energy they use.  In the days of incandescent light, Watts was a ballpark figure representation of brightness, but in the age of solid-state lighting, it's meaningless.

It's about here most elected officials just give up and let the utility company handle it.
Dont give in.

There are a lot of factors that need to be considered for the streetlighting task you gave, but as a very generic example, an arterial roadway with medium pedestrian conflicts on smooth asphalt would have 1.1 footcandles of illumination at the road surface, if the ANSI / IESNA "Illuminance Method" design criteria were used. 
More pedestrians, additional vehicle conflicts or changes in the road surface reflectivity will yield different numbers, as would alternatively using the "Luminance Method" or the "Small Target Visibility" method.

If you want to dive into the real numbers, get a copy of "American National Standard Practice for Roadway Lighting" which is also known as ANSI/IESNA RP-8-00.  I think it's a bit pricey, so you might check your library first:  ISBN # 0-87995-160-5

http://www.ies.org/store/product/roadway-lighting-1028.cfm
Preview: http://www.techstreet.com/products/preview/739518

[heironymouspasparagus]

For starters...
100 Watts incandescent isnt the same as 100 Watts Fluorescent which isnt the same as 100 Watts Sodium which isnt the same as 100 Watts Metal Halide which isnt the same as 100 Watts LED.

Watts is watts is watts.... 100 watts in an LED light is the same as 100 watts in an incandescent....  now, if you are talking 100 watt EQUIVALENT light from an LED as compared to an incandescent, then there is a huge difference (5 or 10 to 1 or so....).  Or the 100 watts LED would give that much more lighting than 100 watts incandescent.  Always gotta have more information than just watts when talking lighting - the story is incomplete.

Actually, VA may be a more accurate measure, due to the inductive methods used in sodium....

[heironymouspasparagus]

Alright, I just thought that the document was interesting and was worth sharing.

It was interesting.  And was worth sharing.  Don't worry about random comments...ask patric if he read the whole thing.  The focus was not just for stargazing, even though put out by an observatory.  Even if no one was interested in seeing stars, there were several other very good stand alone points made.  Just a really great bonus if we could still see the night sky...!!

Plus, more effective lighting might just keep enough of a glow from escaping the planet, such that the alien watchers might miss lower levels of light and not notice us!!

[Ed W]

...

Plus, more effective lighting might just keep enough of a glow from escaping the planet, such that the alien watchers might miss lower levels of light and not notice us!!

Shhhh...the aliens are already here. Have you looked at the people in a Dollar General? They're not from this solar system.

And one serious geek point - reflector design is just as important as wattage.

Sent from my SPH-L720 using Tapatalk

[Cetary]

I also wanted to share this. It's a CCT comparison between the warm whites. It's 2700 k vs. 2800 k vs. 3200 k.

http://i01.i.aliimg.com/img/pb/834/569/257/1279099510626_hz-myalibaba-web5_3098.jpg

Any thoughts?

Also, I've been looking around a lot, and I haven't found any pictures of how a complete warm white LED setup looks with cobra head fixtures. Does anyone know of any?

[patric]

And one serious geek point - reflector design is just as important as wattage.

Reflector design is the heart of good Full-Cutoff Optic fixtures that use omnidirectional lamps like Sodium and Metal Halide.
It's the reflector that determines the "shape" of the light the fixture projects on the ground.
http://www.agi32.com/kb/index.php?article=77

LEDs, however, are directional, so most dont even have a reflector.  Instead the luminaire classification (projected pattern) is determined by the backplane on which the LEDs are attached.

Geek out.

[PonderInc]

I caught a terrific interview on Studio Tulsa yesterday by the author of a book about the importance of dark skies, and how our bad lighting is affecting our health and safety.  

He made great points about the fallacy of more light = more security, and talked about the billions of dollars that are wasted each year by inefficient, non-shielded light fixtures.  Also interesting was the notion that as you increase the brightness in various locations around the city, people think they need more and more light because their eyes never really dilate. So you have super-bright areas, and then what your eyes perceive as "shadows."  In cities where the lighting is shielded and consistent, your eyes adjust and you need far less light to see effectively throughout the city.

Here's the Studio Tulsa interview:
http://publicradiotulsa.org/post/searching-natural-darkness-age-artificial-light

The book is called: The End of Night: Searching for Natural Darkness in an Age of Artificial Light

"Bogard considers our affinity for artificial light, the false sense of security it provides, and its implications.... Bogard urges readers to weigh the ramifications of light pollution and our failure to address them, illustrating his arguments with photographs that prove his point."

[patric]

Also interesting was the notion that as you increase the brightness in various locations around the city, people think they need more and more light because their eyes never really dilate. So you have super-bright areas, and then what your eyes perceive as "shadows."  In cities where the lighting is shielded and consistent, your eyes adjust and you need far less light to see effectively throughout the city.

Ever notice how many people who have a streetlight in their front yard, have also had PSO add another in their back yard?

It's called "ratcheting" and it's a product of homeowners who are unable to see much beyond the city streetlight because their eyes are trying to adapt to the overly-bright pool of light, which in turn makes everything else appear darker... so they add yet another overly-bright light.

An article in today's Whirled lists the things the city plans to look at to address the surge in pedestrian fatalities, and nowhere do they even mention the effects of glare and poorly-planned lighting:

Tulsa officials plan safety improvements in area where auto-pedestrian accident killed toddler

The lives of the Corrie family were forever changed at 7:20 p.m. Nov. 11, the time and date of a south Tulsa auto-pedestrian collision that killed Marshal Corrie, their soon to be 2-year-old son, grandson and brother.
The accident took place just north of 63rd Street and Peoria Avenue near the Warehouse Market grocery store. It involved an out-of-town driver who was unfamiliar with what sources say is a pedestrian-heavy area because of the several apartment complexes in the vicinity.

During the past five years 42 people have died because of auto-pedestrian accidents in Tulsa, according to Officer Craig Murray, the Tulsa Police Department's traffic safety coordinator.
Changes scheduled for next month include lowering the speed limit in addition to installing static signs and crosswalk markings, she said.
In the long-term, the city is working with a consultant for a mobility study of the area, Allen said. Longer-term treatments will depend on the study's findings.

Mobility studies assess the safety, functional performance and service quality experienced by all users on an urban street corridor to identify needed improvements to achieve performance measures, Allen said.

The study will consider factors that include roadway geometry, traffic volume, pavement condition, speed limit, crash history, vehicle and pedestrian access, intersection control type, signal timing data, on-street parking, sidewalk widths and transit data.

http://www.tulsaworld.com/news/local/tulsa-officials-plan-safety-improvements-in-area-where-auto-pedestrian/article_a4ff7ac4-a31b-5916-9f92-b960a10ad991.html

Poor choices of street lighting are not the only sources of glare in that area.  
Commercial lighting often overwhelms municipal lighting, until someone complains (citing one of the few lighting ordinances Tulsa has; Title 42, Section 1303-C).
In the meantime, reducing blinding glare from taxpayer-funded city lighting is completely doable, costs less in the long run, and should be a public safety priority.  
I know there are people in both the police department and Public Works who "get it" with regard to glare-prone lighting, but we need to put that knowledge into motion.