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.
