tag:blogger.com,1999:blog-3102538965694240940.post5064086554968676869..comments2024-02-24T06:21:30.987+01:00Comments on A view from the cycle path: LED street lightsDavid Hembrowhttp://www.blogger.com/profile/14543024940730663645noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-3102538965694240940.post-53520816476259403192009-10-19T17:35:30.505+02:002009-10-19T17:35:30.505+02:00I love the design of that junction - stopping the ...I love the design of that junction - stopping the cyclist with turning traffic from behind appoaching at, what, 120 degrees?! All 'facility' designers should be forced to go spend a month cycling in the Nederlands to see how it is done properly.Robhttps://www.blogger.com/profile/16094081689229845843noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-38046282956203304422009-10-19T15:19:02.009+02:002009-10-19T15:19:02.009+02:00It's worse than you describe -- the (relativel...It's worse than you describe -- the (relatively) bright lights in the pavement, make it impossible for you see the markings. That's pretty appalling. Where they (bluish) white? That would be worst of all -- amber, at least, does not take out your night vision quite so efficiently.dr2chasehttps://www.blogger.com/profile/16320828055999939449noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-65106504328467798432009-10-19T15:06:35.953+02:002009-10-19T15:06:35.953+02:00Duncan: I've seen exactly the same thing in Ca...Duncan: I've seen exactly the same thing in Cambridge. In fact, I <a href="http://www.freewebtown.com/cambridgecycling/girton.jpg" rel="nofollow">took a photo of them</a>. Unfortunately, it's not actually very good.<br /><br />The problem with these is that they are in the pavement shining upwards, so don't actually light up the surface you ride on. The result is that they tell you David Hembrowhttps://www.blogger.com/profile/14543024940730663645noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-14283219230542080972009-10-19T14:53:02.785+02:002009-10-19T14:53:02.785+02:00Hi, just to let you know that Peterborough have be...Hi, just to let you know that Peterborough have been using solar powered LED lighting for their cycle paths although these are 'route markers' rather than streetlights. (sorry about long web link - only available from Google's cache it seems: http://209.85.229.132/search?q=cache:F8GVtr56zIkJ:www.peterborough.gov.uk/page-11697+peterborough+led+lighting+cycle+path&cd=1&hl=en&Duncanhttps://www.blogger.com/profile/13359303704828663733noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-1239548637106557642009-10-16T22:54:36.294+02:002009-10-16T22:54:36.294+02:00dr2chase: If I could find an email address for you...dr2chase: If I could find an email address for you I'd have replied in private. Please, please, no more "LED weenie" stuff on this blog ! It's really not what it's for. If you want to reply, my email address is on the RHS of every page on my blog.<br /><br />Neither of us are party to the reason why the green colour was chosen, nor when the decision was made, I think there David Hembrowhttps://www.blogger.com/profile/14543024940730663645noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-42516369557829719762009-10-16T21:25:31.162+02:002009-10-16T21:25:31.162+02:00(I thought I replied to your reply, maybe I forgot...(I thought I replied to your reply, maybe I forgot to finish.)<br /><br />As I read it, despite what the Wikipedia link claims, white LEDS are in fact more efficient than a green+red combo, at least in terms of how well it works for our vision. If you look at the product data sheets for modern power LEDs (e.g., CREE XRE, or Luxeon Rebel), you find that the green LEDs are at best equal in their dr2chasehttps://www.blogger.com/profile/16320828055999939449noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-78011143487050291012009-10-16T21:06:30.918+02:002009-10-16T21:06:30.918+02:00@Anneke: 30% of men have a degree of red-green col...@Anneke: 30% of men have a degree of red-green colourblindness so may also not be effected by the lights either! Could be an interesting experiment to study which lights have the higher accident or near miss rate!Robhttps://www.blogger.com/profile/16094081689229845843noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-80669735613692901412009-10-16T18:47:07.153+02:002009-10-16T18:47:07.153+02:00I've been fitting 'warm white' LED dow...I've been fitting 'warm white' LED downlighters in the house which look just the same colour as halogens to me. I've got older 'cool white' ones in the workshop which look more photo-flash in colour.<br />But I'm guessing for street lighting that the directional nature of LEDs is helpful - the sodium lighting in these parts seems to be aimed every which way. I'm Robhttps://www.blogger.com/profile/16094081689229845843noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-14600908434050621982009-10-16T13:17:08.833+02:002009-10-16T13:17:08.833+02:00Also, night animals aren't as affected by red ...Also, night animals aren't as affected by red and green light as whitre or yellow.Annekehttps://www.blogger.com/profile/13303232666607267415noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-26134274828027543922009-10-16T13:16:41.211+02:002009-10-16T13:16:41.211+02:00Except that it doesn't seem to work the way yo...Except that it doesn't seem to work the way you say it does. If you consider the latest from Philips/Luxeon, the "Rebel", green and white have equal efficiency, but red has less. So as soon as you mix red in there, you lose. And, for whatever reason, the latest (neutral) white from CREE is about 15% brighter.<br /><br />Maybe they did it this way to avoid blue, maybe they dr2chasehttps://www.blogger.com/profile/16320828055999939449noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-3039353838822948192009-10-16T06:32:51.313+02:002009-10-16T06:32:51.313+02:00dr2chase: I have to admit that I'm not a great...dr2chase: I have to admit that I'm not a great fan of the funny colour as such. There are also white LED street lights at other locations in the city and I suspect over time that these will be more popular.<br /><br />The green and red mix at least gives some colour rendition and as a result it's a lot nicer than orange sodium lamps. Why green and red ? Because these colours can be David Hembrowhttps://www.blogger.com/profile/14543024940730663645noreply@blogger.comtag:blogger.com,1999:blog-3102538965694240940.post-56036038173106262042009-10-16T04:29:57.557+02:002009-10-16T04:29:57.557+02:00Okay, so speaking as an LED weenie, why green and ...Okay, so speaking as an LED weenie, why green and red? You can get pretty good, and somewhat more efficient, light from a modern so-called "neutral-white" LED. I use some in my kitchen, if there is any problem with the light, it might have a hair of a greenish tinge, but nothing like that in the photo here. The spectrum is quite civilized. (For anyone who is not quite an LED weenie,dr2chasehttps://www.blogger.com/profile/16320828055999939449noreply@blogger.com