Expressway Lights

[patric]

Ever wonder why you can safely drive 70-80mph on an unlit highway or turnpike at night, yet doing 55mph on a Tulsa expressway is a deathwish if there's a couple of streetlights out?

Architectural Lighting Magazine just published this bit on road markings being neglected in favor of much more expensive (but effectively questionable) lighting:

http://www.archlighting.com/architecturallighting/search/article_display.jsp?vnu_content_id=1002463586

quote:     The article "On The Road with Light" presented a detailed review of the three methods for roadway lighting calculations. Not discussed was whether or not roadway lighting is warranted at all, and if warranted, to what degree. RP-8 (American National Standards for Roadway Lighting) does not address criteria for "when" roadway lighting is necessary�the standards only apply to continuous lighting. And what warranting criteria are to be used for "spot illumination", which applies to many if not most local roads? There are fundamental questions on the circumstances under which roadway lighting is warranted, and these questions deserve careful consideration by public officials and lighting engineers:

   1. With fierce competition for limited public financial resources, under what criteria does the investment in roadway lighting provide a reasonable return on investment in terms of collision avoidance?

   2. If roadway lighting does provide an appropriate return on investment, does that additional level of collision avoidance provided by lit roads apply at all hours, from dusk to dawn, or is most of the benefit realized before midnight, after which traffic volume may be negligible? Would turning streetlights off after midnight significantly contribute to energy conservation without significantly affecting rates of collision?

   3. Could passive alternatives such as reflective pavement markings provide a similar degree of public safety, and if so at what cost?

   In the 1970s, in response to an energy crisis, CalTrans decided to remove all roadway lighting from limited access freeways, except for those located at the interchange. In the 30 years since these roadway lights were taken down, CalTrans has not seen the need to reinstall roadway lighting on freeways. CalTrans has now commissioned a study, due for completion in 2008, to determine whether roadway lighting is necessary even at interchanges.

   On local roads, most lighting is mounted on wood utility poles, and the spacing requirements are based on the weight distribution factors for the wires. Streetlights mounted on utility poles may offer little, if any, public benefit in terms of collision avoidance.

   100 years ago car headlights were very weak, compared to today. Back then there were few examples of roadway striping or reflective markers on the roads.

   The question for future research will be to determine the public benefits gained from investment in streetlights, and to compare those benefits to other areas of investment like healthcare or public safety. Until those questions are answered, CalTrans example of not using roadway lighting for freeways deserves careful consideration.

Just some light reading...

[patric]

Does this sound familiar to anyone?

http://blog.syracuse.com/kirst/2008/01/lights_out.html

Nice to know Tulsa's not an island, after all...

[patric]

Ive not been Public Works director Hardt's biggest fan, but I will admit I think he has a clue here:

Concerning highway lightning, Hardt said there is conflicting evidence that highway lighting adds to safety.

He says there is a safety benefit for lighting along arterial streets where pedestrians might come into cars and that lighting would not be affected.
http://www.newson6.com/global/story.asp?s=11807898

Public reaction has been good -- people are driving a little more cautiously, they are finding that their headlights were doing most of the work all along, and the doom-and-gloom talk radio predictions of a bloodbath in the dark havent materialized. 

If we are going to do away with unneeded expressway lighting, Public Works should undertake the task of making sure interchanges, ramps and underpasses are rewired so that they work independently of the decommissioned straightaway sections.

I would also start removing the decommissioned poles and fixtures before the copper and aluminum thieves do.
What isnt saved as spares can be sold off to bring in income.

Keep in mind there is a trade-off to eliminating unnecessary roadway lighting:  Reflective lines and markers must  be maintained, especially in winter when there is a lot of abrasive sand and salt on streets that grind away at  the painted lines, but in the long run it should cost much less than all the electricity and manpower to maintain less-effective expressway lights.

[patric]

Despite the perception that unlit expressways are more dangerous than lit ones, TPD's numbers seem to indicate that, as far as crashes, there is no real benefit to having expressways lit:


Drivers are complaining to the city and to police.
"I know there's some concern," says Officer Craig Murray.

He did some checking to find out if driving in the dark is causing more crashes.

The city turned off the lights November first.
From then until December 31 there were 72 crashes on the Broken Arrow expressway. 43 percent of those happened after dark.

Officer Murray checked the same time frame during the previous year.
The numbers were similar – 73 crashes and 45 percent after dark.
http://www.fox23.com/news/local/story/Highway-Lights-Out/-eHVJCEx-0qXm5Dmg034vQ.cspx

That's consistent with other findings across the nation.

[dsjeffries]

Source: http://www.newson6.com/Global/story.asp?S=11805839

Are LED Streetlights Worth The Upfront Costs?
Posted: Jan 11, 2010 10:32 PM CST Updated: Jan 12, 2010 10:01 AM CST

By Jennifer Loren, The Oklahoma Impact Team

TULSA, Oklahoma -- As cities in the Sooner state scrutinize their bottom lines, some new, green technology is enticing them with promises of long-term savings. But is LED (Light Emitting Diodes) lighting worth the up front cost?

In Tulsa, the new city mayor inherited a city so strapped for cash, officials turned off street lights over all the major highways. The mayor's Chief of Staff, Terry Simonson, said having dark highways is dangerous for drivers.

"Like when we had the snow at Christmas time it was particularly hard for people to see through the storm in the dark on the expressway," said Simonson.

Simonson and Tulsa Mayor Dewey Bartlett think they've come up with a bright idea to turn the lights back on and save the city money. The city is applying for $750,000 in stimulus money to replace some current street lights with LED lights. If approved, the money would come from the Department of Energy and be part of the city's energy efficiency strategy.

"Which ever might be the darkest and the most traveled, why don't we start there? Either every light, every other light, lets just get started getting out of the darkness," said Simonson.

Using stimulus money up front is a relatively quick fix that could bring the city long-term benefits.

Current city street lights range from 100 to 400 watts. Tulsa has about 1,300 400-watt street lights. They use about 70 percent more energy than new LED street lights which are about 120 watts.

"This is a product that's going to revolutionize everything we know about lighting," said Fred Hannah, owner of Lektron Incorporated in Tulsa.

Lektron is the company that installed several LED lamps outside the Tulsa County Courthouse. Hannah said LEDs not only reduce energy consumption, they also reduce maintenance costs because the lights themselves last about twice as long. Some lights won't need to be changed for more than 20 years.

"Then the savings over a period of years is just incredible. It adds up to not hundreds of thousands of dollars; It adds up to millions of dollars," said Hannah.

Hannah said LED technology is getting better every day. In fact, he admits, there is a downside for cities getting in on LED technology at this stage. The initial cost is greater on the product. According to traffic engineers at the City of Tulsa each LED "cobra head" costs about $900. Standard street lights cost just $200 each.

That's one reason the City of Oklahoma City is not yet sold on LED lighting, although LEDs are being considered for their Downtown 180 streetscape project.

"You know there's not a whole lot of track record-type of information out there because it's relatively new," said Dennis Clowers, with the City of Oklahoma City

Oklahoma City engineers want to test the lights for a year before they commit to investing in them. They have concerns that the current technology is not good enough. One complaint with LEDs is that the light they shine is too directional. That means the city may have to buy more lights to cover the same amount of space.

"But if you have to use ten times as many lights then you're really not saving anything. So that's the kind of information we need to gather before we can make a decision," said Clowers.

Oklahoma City is not applying for stimulus money to fund LED lights.

Back in Tulsa, city administrators say time is not on their side. Stimulus money must be used now or there may not be a light at the end of the tunnel.

"The money would be gone. So we have a little window to do something with," said the Tulsa mayor's Chief of Staff, Terry Simonson.

There is so much wrong with this article it baffles me. The fact the LEDs are directional is not a downside--it's a benefit. When light is directed (and aimed) more accurately, it creates less glare and light pollution, which makes it safer for pedestrians and motorists. LEDs also uses much less energy and (contrary to Mr. Simonson, who is not a lighting expert), poles can be farther apart because the light shines only where it is needed.

Dark streets are much safer than lighted ones when we have bad fixtures that cast light in all directions--they create dangerous glare. Lights can become a hazard when done improperly.

And from my own experience driving around on Tulsa's now-dark highways, it's actually easier to see at night. Someone besides AEP-PSO needs to inform our city leaders about lighting. More does not always mean better.

[PonderInc]

I have no problem with turning off the expressway lights.  It's far more important to have well marked lanes (stripes painted with good, reflective paint) than it is to turn nighttime into day. 

While I'm not worried about expressway lights being out, I do think that digital billboards negatively affect public safety.  Funny that everyone agrees that "texting while driving" is bad... But our city councillors are OK with fast-changing, highly distracting, overly bright digital billboards that continuously take drivers' attention off the road.

Someday, we'll figure this out.

One other thing....
Last month, I drove past Oneok Field when the stadium lights were turned on at night.  The lights were incredibly bright, and the height of the freeway put drivers much closer to the source of the lights than normal.  (You're also much closer to the stadium than normal...for instance, driving past Skelly Stadium.) 

It was definitely distracting...and I'm especially concerned for those driving east on 244.  This is where, if you're looking over at the stadium, you may not notice the fast-approaching "fork" in the road...where 75 splits off to go north.  Hope they increase the number of crash barrels in that location!

[patric]

There is so much wrong with this article it baffles me. The fact the LEDs are directional is not a downside--it's a benefit. When light is directed (and aimed) more accurately, it creates less glare and light pollution, which makes it safer for pedestrians and motorists. LEDs also uses much less energy and (contrary to Mr. Simonson, who is not a lighting expert), poles can be farther apart because the light shines only where it is needed.

Dark streets are much safer than lighted ones when we have bad fixtures that cast light in all directions--they create dangerous glare. Lights can become a hazard when done improperly.

And from my own experience driving around on Tulsa's now-dark highways, it's actually easier to see at night. Someone besides AEP-PSO needs to inform our city leaders about lighting. More does not always mean better.

Its tragic the new mayor is getting this sort of advice on streetlighting.

Ill go down the article:

Simonson says "having dark highways is dangerous for drivers".
That's a perception that isnt backed up by facts.  TPD's numbers show no real increase in accidents without expressway lights compared to a year ago with lights, and that's consistent with findings all over the country.

Simonson says "when we had the snow at Christmas time it was particularly hard for people to see through the storm in the dark on the expressway."
Reflective lines and signs are designed to reflect light back from the direction it came, such as from your headlights.  Their retro-reflective properties dont work with light at other angles, such as streetlights.  You can see this when it's rainy and the glare off of pavement from streetlights can be brighter than the light reflected from headlights.  In this instance, any lines on the street would show up in silhouette, if they were visible at all.
And, of course, once the snow covers the road, neither streetlights nor headlights will penetrate.  In heavy snowfall (like Christmas eve), streetlights only add to "whiteout" conditions, and when it's that bad, light from any source wont really help and you should get off the road and be seeking immediate shelter.

Simonson says  "Which ever might be the darkest and the most traveled, why don't we start there?"
No.  The "warranting" process for streetlights should be weighed on how much benefit, if any, the placement of a streetlight would bring. 
For example, a straightaway on the BA expressway might be dark and heavily traveled, but unless there are specific needs for streetlighting that cant be accomplished with something more effective and cost-efficient (such as properly maintained reflective lines and signage, referred to as "passive" illumination) then lights arent warranted.

Where a light would be warranted would be those areas where there are special circumstances, such as pedestrians in or near the roadway, or vehicular conflicts such as intersections, interchanges, ramps or other dynamic traffic conflicts that cant be adequately addressed with just reflective markings. 
Currently we let the people who sell electricity decide where and how much streetlighting we buy from them.  Bad practice.

"One complaint with LEDs is that the light they shine is too directional. That means the city may have to buy more lights to cover the same amount of space."
No.  That'a an obsolete "uniformity" argument that utilitiy companies have used to resist using "Full-cutoff" or low-glare streetlighting. 
It relies on outdated theory that every inch of a street must be lit even if it means considerable overlapping, but this hasnt been aprt of the IESNA recognized practice since at least 1999 (when ANSI/IESNA released RP-8-00 "American National Standard Practice for Roadway Lighting").
The utility companies still spout that because it translates to more electrical sales on the backs of taxpayers, though.  Dsjeffries pretty well hit the nail on the head recognizing that low-glare lighting is easier to achieve when you actually have control over the light's directionality.

Simonson says "The money would be gone. So we have a little window to do something with."
Maybe this time, but does anyone really believe there wont be additional grants in the months and years to come?

LED streetlighting is still an emerging technology.  It will continue to improve with time, but I will concede the temptation to use some money now to replace more expensive and wasteful streetlighting is valid.
The biggest downside to going with off-the-shelf products right now is that most of the choices will be dated in short time.

Remember early fluorescent lights, with their horrible hues of green and blue making everyone under them look like they are zombies?  That's where we are on LED streetlighting.
Now, that might be ok for some applications where color rendition isnt important, but if we go that route we need to select those locations carefully.

Otherwise, we should wait for LED's to mature to the point where they have more realistic color rendition (like that of incandescent lighting, around 3000 degrees Kelvin) or learn to live with the blues.

[rwarn17588]

One other thing....
Last month, I drove past Oneok Field when the stadium lights were turned on at night.  The lights were incredibly bright, and the height of the freeway put drivers much closer to the source of the lights than normal.  (You're also much closer to the stadium than normal...for instance, driving past Skelly Stadium.) 

It was definitely distracting...and I'm especially concerned for those driving east on 244.  This is where, if you're looking over at the stadium, you may not notice the fast-approaching "fork" in the road...where 75 splits off to go north.  Hope they increase the number of crash barrels in that location!

It seems that St. Louis drivers on Interstate 64 (aka Highway 40) handle the lights from the very close Busch Stadium just fine ...

[patric]

For the newcomers to the board, we also discussed LED streetlights (and others) in detail with


Better Streetlights for Tulsa

[Hawkins]

I think the expressways need to be lit.

People stranded, mentally handicapped, or out working on a broken-down car at night are all at risk by unlit roadways. And it gets dark now around 6pm.

The city, idiotic as it is run, can't even afford to keep the lights on.

Upgrading to LED lights would save a huge percentage of the cost of having these lights on. I didn't read the article, but what do these new LED street lamps use, like 20% of the power of the current bulbs? That's an 80% reduction in the city's highway light budget year after year once the upgrade is done.

Whether to do it now or wait until LEDs are more affordable and technologically advanced is the only question. Eventually though, it would be pretty dumb not to make the upgrade.

--

[rwarn17588]

Upgrading to LED lights would save a huge percentage of the cost of having these lights on. I didn't read the article, but what do these new LED street lamps use, like 20% of the power of the current bulbs? That's an 80% reduction in the city's highway light budget year after year once the upgrade is done.

Whether to do it now or wait until LEDs are more affordable and technologically advanced is the only question. Eventually though, it would be pretty dumb not to make the upgrade.

Switching to LEDs is all good and well. But if you don't have the money to keep the regular lights on, you sure as hell don't have the money to upgrade to LED lighting, which ain't cheap.

[patric]

I think the expressways need to be lit.

People stranded, mentally handicapped, or out working on a broken-down car at night are all at risk by unlit roadways. And it gets dark now around 6pm.

The city, idiotic as it is run, can't even afford to keep the lights on.

Upgrading to LED lights would save a huge percentage of the cost of having these lights on. I didn't read the article, but what do these new LED street lamps use, like 20% of the power of the current bulbs? That's an 80% reduction in the city's highway light budget year after year once the upgrade is done.

Whether to do it now or wait until LEDs are more affordable and technologically advanced is the only question. Eventually though, it would be pretty dumb not to make the upgrade.

Im not in agreement that we should light expressways end-to-end because some motorists dont bother to keep a flashlight in their car.
...and I can easily cite many, many instances this year where people were hit on lighted expressways or in broad daylight, but the fact that the crash rate between lit and unlit periods is virtually identical speaks volumes as to the "safety" claims of the expressway lights.

At expressway speeds, pedestrians should never assume drivers can react fast enough to avoid them, and this is true whether it's noon or midnight.   

I dont like the idea of turning off interchange lighting, though, as there are documentable safety benefits to highlighting conflict areas like ramps and other intersections.  It would be smart of Public Works to re-wire those circuits so they could be isolated from unnecesary lights.

[Hawkins]

Im not in agreement that we should light expressways end-to-end because some motorists dont bother to keep a flashlight in their car.
...and I can easily cite many, many instances this year where people were hit on lighted expressways or in broad daylight, but the fact that the crash rate between lit and unlit periods is virtually identical speaks volumes as to the "safety" claims of the expressway lights.

At expressway speeds, pedestrians should never assume drivers can react fast enough to avoid them, and this is true whether it's noon or midnight.   

I dont like the idea of turning off interchange lighting, though, as there are documentable safety benefits to highlighting conflict areas like ramps and other intersections.  It would be smart of Public Works to re-wire those circuits so they could be isolated from unnecesary lights.

Let me break it down for you a little bit better.

People are generally dumb. Both people on foot and people in cars make mistakes. They don't pay attention, many don't have flashlights or hazard cones readily available.

People in cars see things better, and have more time to react when the road ahead of them is lit up.

Tell me any of the above statements are not true.

[dsjeffries]

Tell me any of the above statements are not true.

It's not true.

[patric]

Let me break it down for you a little bit better.

People are generally dumb. Both people on foot and people in cars make mistakes. They don't pay attention, many don't have flashlights or hazard cones readily available.

People in cars see things better, and have more time to react when the road ahead of them is lit up.

Tell me any of the above statements are not true.

You would have to ask highway workers how many of their co-workers they have seen hit and killed under broad daylight, or bright streetlights.   Hazard cones notwithstanding.
If anything, people do more stupid things given the false sense of security that streetlights provide.  Drivers drive faster on lit roads than unlit roads, and pedestrians make false assumptions that they can be seen.

As it is now, drivers are being forced to slow down a bit and pay attention because the expressway isnt lit like a downtown street.