I saw one with four phases down the street from my school. They're doing construction there. Is there ANY REASON a CMS should use more than three phases? And three phases only if it's ABSOLUTELY NECESSARY. :confused: :banghead:
Quote from: bootmii on October 12, 2012, 03:53:08 PM
I saw one with four phases down the street from my school. They're doing construction there. Is there ANY REASON a CMS should use more than three phases? And three phases only if it's ABSOLUTELY NECESSARY. :confused: :banghead:
Permanent ones on I-10 westbound between Acadian Thwy and the 10/110 split tell trucks that they are advised to stay in the center lane to merge onto the MRB. Since I go that way daily, I've seen the signs change from "Stay in right lane" (which meant stay in the right lane of the ramp) to "Take right lane to MRB" (also meaning the right lane of the ramp, not 10), to the new "TRUCKS USE CTR LN TO MRB, TRVL 35 MPH". It also alternates with just "TRUCKS STAY IN CTR LANE TO USE MRB." I've also seen one sign on 10E between LA 415 and LA 1 say "ACDNT BLCK RT LN, EXPCT DLY AHEAD ON MRB." Too many acronyms!
It would probably be a lot less indecipherable if I knew what the Murb was.
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Quote from: Brandon on October 12, 2012, 07:11:05 PM
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Given the way Illinoisans(?) drive reaching the 1,000 mark may happen, 3 a day would do it (easy peasy).
In the 70's Delaware had a billboard outside the Troop 3 state police substation showing how many died the current year and the previous year, I never paid it much attention tho because I was 17-26yo and bullet proof :rolleyes:.
Back on topic, the worst cms's r the 1s' that use acronyms that are not well known 2 non-residents. :-)
Quote from: agentsteel53 on October 12, 2012, 05:07:00 PM
It would probably be a lot less indecipherable if I knew what the Murb was.
Mississippi River Bridge? I had to think about that one and I've lived in Baton Rouge for 4 years!
Of course they could call it the HWB (for Horace Wilkinson Bridge (http://en.wikipedia.org/wiki/Horace_Wilkinson_Bridge)) but then that would really confuse the heck out of people.
Quote from: Brandon on October 12, 2012, 07:11:05 PM
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Texas is doing that, too. Back from my trip to Seattle I was driving east on I-30 through D/FW. I think the number there was over 1,000.
Quote from: Brandon on October 12, 2012, 07:11:05 PM
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Where's that awkward laugh smiley?
You're ahead of (or behind?) Tennessee, which was using something similar along I-240 in Memphis back in August.
Of course, I'm wondering if that includes out-of-state visitors' fatalities, because there's nothing worse than being an uncounted statistic.
ODOT did a horrible one on SH-9 approaching I-35 which said something along the lines of "I-35 NB RAMP 2B CLOSED [date]". It took me several minutes to rack my brain trying to wonder which one was ramp 2B... There isn't an exit 2B on I-35 in Oklahoma, and if there were, it'd be 100 miles to the south and not relevant to a traveler in the vicinity of the sign. Maybe it was an internal ramp numbering designation? If so, which one was Ramp 2B?
I was nearly to work when I realized it was supposed to be text speak for "to be".
Here's another one I've never managed to puzzle out. My guess is that some random person might have reprogrammed it–but as you can see it's in an active work zone, so you'd think someone would have caught it and changed it back...
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYDw8Z.jpg%3F1&hash=89a2d331a612705d48174db2ed2aa06d39de8c6f)
Quote from: allniter89 on October 12, 2012, 08:25:32 PM
Quote from: Brandon on October 12, 2012, 07:11:05 PM
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Given the way Illinoisans(?) drive reaching the 1,000 mark may happen, 3 a day would do it (easy peasy).
In the 70's Delaware had a billboard outside the Troop 3 state police substation showing how many died the current year and the previous year, I never paid it much attention tho because I was 17-26yo and bullet proof :rolleyes:.
Back on topic, the worst cms's r the 1s' that use acronyms that are not well known 2 non-residents. :-)
Delaware still maintains these signs (not a billboard, but rather a 3' x 3' sign) outside their troop headquarters with this year's fatals vs. last year's fatals.
BTW, as of Friday, this year is down slightly.
On my trip up to the White Mountains at the end of August I noticed New Hampshire doing the same thing. Every VMS I saw statewide displayed the fact that that month there had been "17 NH traffic deaths". Almost as if they were bragging about it.
Quote from: deathtopumpkins on October 15, 2012, 09:35:35 AM
On my trip up to the White Mountains at the end of August I noticed New Hampshire doing the same thing. Every VMS I saw statewide displayed the fact that that month there had been "17 NH traffic deaths". Almost as if they were bragging about it.
Maybe that's a bad thing, and shows that the message isn't getting across. According to this news article, that figure is actually UP 19% from last August. http://www.unionleader.com/article/20120901/NEWS07/709019951 (Per the article, 20 deaths in 18 Accidents occurred during the month...which means there was a few additional after you saw the sign.)
I doubt they're bragging about more deaths!
Hampton Roads VMS have a significant number of pixels permanently on or permanently off. Time to get a new technology.
Quote from: Steve on October 20, 2012, 02:21:34 PM
Hampton Roads VMS have a significant number of pixels permanently on or permanently off. Time to get a new technology.
Interesting. VDOT's Northern Virginia has recently replaced many VMS panels with dramatically better units.
Wait, I saw one on SB Mission in Colma that had five phases. :banghead: :verymad:
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
I think most of these examples will come from trying to fit too much information on signs which can only display 3 lines of 8 characters. We need more of those full-dot-matrix signs where the text size can be varied. Not that I advocate tiny text in construction zones, but strictly 8 characters per line allows very few practical combinations of 2 words to share the same line.
Quote from: thenetwork on October 26, 2012, 12:28:01 AM
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
Do you mean flip-disk displays?
http://en.wikipedia.org/wiki/Flip-disc_display
Quote from: abc2VE on October 26, 2012, 08:50:45 PM
Quote from: thenetwork on October 26, 2012, 12:28:01 AM
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
Do you mean flip-disk displays?
http://en.wikipedia.org/wiki/Flip-disc_display
Noooo...Not the Ferranti-Packard type, these were far worse than those. I tried to find a photo of one, but couldn't -- these babies have (mercifully) been long gone for at least 10-15 years. If someone has a photo of one, please post it!
a couple years ago in Austin, TX --
http://www.youtube.com/watch?v=emPPKjyU_NI
I have seen "Testing 123456789 ABCDEFGHI"
I have also seen "I-95/128: 16 MILES 14 MIN". That's way over the speed limit of 65.
Quote from: 1 on August 10, 2013, 06:37:41 PM
I have also seen "I-95/128: 16 MILES 14 MIN". That's way over the speed limit of 65.
16 miles @ 65 mph = 14 minutes, 46 seconds. Maybe they're rounding down.
Quote from: thenetwork on October 26, 2012, 12:28:01 AM
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
You mean something like a sixteen-segment display?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwindways.org%2Fpersonal_page%2Fstockticker%2F16-seg%2520Character%2520Set.gif&hash=c793b1a864c50a1cbc0e0c2be73473bfb446a2b0)
Quote from: vtk on October 26, 2012, 07:01:04 AM
We need more of those full-dot-matrix signs where the text size can be varied.
Maybe someone has already done this, but wouldn't it be possible to have a VMS that essentially worked like a giant e-ink screen–like you have on a Kindle? The sheeting behind could be retroreflective and require no backlighting, and since electricity is only needed to change the display, the e-ink display could be almost entirely non-powered. And of course such a screen would also be able to reproduce perfect FHWA alphabets, route shields, and diagrammatics. It would be a quantum leap ahead of our current VMSes–which are about as technically advanced as the game board on 1970s-era Family Feud.
Perhaps it's possible but just too expensive at this time.
^^ The technology is used on a smaller scale in places, such as in Seattle where the variable speed limit signs actually display the speed limit in FHWA series E.
Quote from: deathtopumpkins on October 15, 2012, 09:35:35 AM
On my trip up to the White Mountains at the end of August I noticed New Hampshire doing the same thing. Every VMS I saw statewide displayed the fact that that month there had been "17 NH traffic deaths". Almost as if they were bragging about it.
I think in the White Mountains it should say "BEWARE TRIPODS."
(I assume I'm not the only one who remembers those books.)
Quote from: 1 on August 10, 2013, 06:37:41 PM
I have seen "Testing 123456789 ABCDEFGHI"
I have also seen "I-95/128: 16 MILES 14 MIN". That's way over the speed limit of 65.
The signs use the actual speed of traffic, not the speed limit. Having a travel time sign that shows you the time at the speed limit would be pointless, since it doesn't matter what the speed limit is if the road is congested.
One example that always strikes me is the new ones on I-95. There's a "6 miles / 4 min" and a "3 miles / 2 min" sign. Those are both ~90 mph, which makes me believe they must be rounded up.
Quote from: deathtopumpkins on August 11, 2013, 12:37:09 AMThe signs use the actual speed of traffic, not the speed limit. Having a travel time sign that shows you the time at the speed limit would be pointless, since it doesn't matter what the speed limit is if the road is congested.
In/around Seattle, if the road is congested, then yes, they use the actual speed of traffic, but they always "max out" at the speed limit. The sign in South Everett 26 miles north of Seattle frequently shows travel times of more than 26 minutes, but never less than 26 minutes.
Quote from: Kacie Jane on August 11, 2013, 07:05:02 AM
Quote from: deathtopumpkins on August 11, 2013, 12:37:09 AMThe signs use the actual speed of traffic, not the speed limit. Having a travel time sign that shows you the time at the speed limit would be pointless, since it doesn't matter what the speed limit is if the road is congested.
In/around Seattle, if the road is congested, then yes, they use the actual speed of traffic, but they always "max out" at the speed limit. The sign in South Everett 26 miles north of Seattle frequently shows travel times of more than 26 minutes, but never less than 26 minutes.
The examples in the part of my post you cut out clearly show that Massachusetts does not max them out at the speed limit. Seems much more useful than the WSDOT ones.
Also, wouldn't having the times max out at the speed limit require more work on the part of whoever is programming the back end of the system?
Quote from: deathtopumpkins on August 11, 2013, 11:28:48 AM
Also, wouldn't having the times max out at the speed limit require more work on the part of whoever is programming the back end of the system?
Not significantly so, I wouldn't think. Just add a couple lines of code to compare the actual travel time to the travel time at the legal speed limit and display whichever is greater.
Quote from: deathtopumpkins on August 11, 2013, 11:28:48 AM
Quote from: Kacie Jane on August 11, 2013, 07:05:02 AM
Quote from: deathtopumpkins on August 11, 2013, 12:37:09 AMThe signs use the actual speed of traffic, not the speed limit. Having a travel time sign that shows you the time at the speed limit would be pointless, since it doesn't matter what the speed limit is if the road is congested.
In/around Seattle, if the road is congested, then yes, they use the actual speed of traffic, but they always "max out" at the speed limit. The sign in South Everett 26 miles north of Seattle frequently shows travel times of more than 26 minutes, but never less than 26 minutes.
The examples in the part of my post you cut out clearly show that Massachusetts does not max them out at the speed limit. Seems much more useful than the WSDOT ones.
Also, wouldn't having the times max out at the speed limit require more work on the part of whoever is programming the back end of the system?
Assuming for the sake of argument the practice of rounding the minutes figure down, 3 miles in "2" minutes could be any speed above 60 MPH but not more than 90 MPH. For 6 miles in "4" minutes, the speed used in the calculation would have to be more than 72 MPH, which indeed makes for compelling evidence that the signs in Massachusetts do not adjust travel times to reflect the speed limit.
As for the programming, imposing a minimum on the displayed travel time is trivial. The minimum amount of time it takes to drive from point A to point B while obeying the speed limit can be precomputed. (Which is more work for someone in the setup process, but not a programming issue.) Then, the bit of programming that controls the sign message needs only to look up that stored value, compare it to the travel time calculated from speed sensors, and use the greater value in its output. I'm fairly sure the travel time signs in Cincinnati and Columbus do this.
I have always seen 16 miles 14 minutes, never 16 and 13, 16 and 15, or 16 and 16. (Of course, when there is traffic, it will change.) Same with 13 miles 12 minutes: never 13 and 11.
I love when a sudden traffic jam occurs and local road agencies have not gotten a chance to update the information. Therefore you are sitting in stopped traffic and it giving you great timing to a place you know is impossible to achieve.
Here's a blog entry from last week that attempts to explain the logic behind what appears on MassDOT's VMSs:
http://www.boston.com/community/blogs/roads_and_rails/2013/08/behind_screens_vms_downtown_detours.html (http://www.boston.com/community/blogs/roads_and_rails/2013/08/behind_screens_vms_downtown_detours.html)
Quote from: bob7374 on August 11, 2013, 09:50:52 PM
Here's a blog entry from last week that attempts to explain the logic behind what appears on MassDOT's VMSs:
http://www.boston.com/community/blogs/roads_and_rails/2013/08/behind_screens_vms_downtown_detours.html (http://www.boston.com/community/blogs/roads_and_rails/2013/08/behind_screens_vms_downtown_detours.html)
QuoteLast year a multi-screen message warned of construction. I transcribed from memory later as "blah blah blah construction ahead masspike blah blah blah 2 left lanes closed". Could have been one screen: "left lanes closed 3 miles ahead." If only they had a brain.
Says the guy that can't remember the message but used it for his ranting example.
Quote from: jeffandnicole on August 11, 2013, 10:54:23 PM
Says the guy that can't remember the message but used it for his ranting example.
Says the guy who apparently missed the point.
Quote from: NE2 on August 11, 2013, 11:41:07 PM
Quote from: jeffandnicole on August 11, 2013, 10:54:23 PM
Says the guy that can't remember the message but used it for his ranting example.
Says the guy who apparently missed the point...
...by a long shot.
Anyways...I have to wonder what DoT pays certain people to calibrate and program changeable message signs. I just hope Montana DoT doesn't make any of these apparent mistakes. I can't say they haven't, but I can't be sure if there have been times where such cases arisen.
Quote from: briantroutman on August 10, 2013, 08:44:34 PM
Maybe someone has already done this, but wouldn't it be possible to have a VMS that essentially worked like a giant e-ink screen–like you have on a Kindle? The sheeting behind could be retroreflective and require no backlighting, and since electricity is only needed to change the display, the e-ink display could be almost entirely non-powered. And of course such a screen would also be able to reproduce perfect FHWA alphabets, route shields, and diagrammatics. It would be a quantum leap ahead of our current VMSes–which are about as technically advanced as the game board on 1970s-era Family Feud.
Perhaps it's possible but just too expensive at this time.
Funny you should say that, because the game board on 1970s era Family Feud worked in essentially the way you describe. Each pixel was a magnetized dot that was black on one side and yellow on the other. Electromagnets refreshed the display. The only difference is than an "e-ink" display would have smaller pixels.
Quote from: Brandon on October 12, 2012, 07:11:05 PM
The worst?
How about IDOT's campaign to show you how many people have dies on Illinois roads this year so far:
763
TRAFFIC DEATHS
THIS YEAR
It's stupid and morbid, IMHO. Of course, I'm rooting for it to pass 1,000. X-(
Plus they put it during rush hour, when I would be more concerned with travel times than this :angry:
Quote from: deathtopumpkins on August 11, 2013, 11:28:48 AMSeems much more useful than the WSDOT ones.
My logic is this. If traffic is light enough that you could get from S. Everett to Seattle in 26 minutes, then you could probably also get there in 22 minutes if you so desired. If you look at it not so much as a strict time measurement, but as a measure of congestion, then the case where you can go 26 miles in 26 minutes represents 0 congestion, and depicting cases of <0 congestion is a bit daft.
(To put it another way, say my personal average speed in ideal conditions on that section of highway were 65 mph, thus taking me 24 minutes to reach my destination. If the screen reads 26 minutes, that means traffic is light enough that I could probably still get there in 24 minutes with only a minimal amount of weaving, if any. If the screen reads 22 minutes, I'm still going to take 24 minutes to get there -- keeping to the right lane, of course. The ability to show speeds faster than the speed limit doesn't actually provide any additional usefulness when it comes to communicating congestion levels.)
Quote from: Kacie Jane on August 12, 2013, 05:20:50 PM
Quote from: deathtopumpkins on August 11, 2013, 11:28:48 AMSeems much more useful than the WSDOT ones.
My logic is this. If traffic is light enough that you could get from S. Everett to Seattle in 26 minutes, then you could probably also get there in 22 minutes if you so desired. If you look at it not so much as a strict time measurement, but as a measure of congestion, then the case where you can go 26 miles in 26 minutes represents 0 congestion, and depicting cases of <0 congestion is a bit daft.
(To put it another way, say my personal average speed in ideal conditions on that section of highway were 65 mph, thus taking me 24 minutes to reach my destination. If the screen reads 26 minutes, that means traffic is light enough that I could probably still get there in 24 minutes with only a minimal amount of weaving, if any. If the screen reads 22 minutes, I'm still going to take 24 minutes to get there -- keeping to the right lane, of course. The ability to show speeds faster than the speed limit doesn't actually provide any additional usefulness when it comes to communicating congestion levels.)
I disagree - to me, being unable to do 5-10 over the speed limit counts as congestion. There is a difference to me between puttering along in a mass of cars barely doing 65 and having an open road to fly along at 75. In my case the latter is 0 congestion, and the former is minor congestion, but still worth of reporting.
The problem with your argument is that you're assuming the speed limit to be the average speed in ideal conditions, which it rarely ever is.
Here's one, from May 2012 at one end of a work zone in Virginia on US 221 between Bedford and Lynchburg:
(//www.alaskaroads.com/expert-delay-sign3_DSC9049.jpg)
Maybe unusual candor from someone on the construction crew (though we always knew what they were best at). But a similar VMS at the other end of the work zone ("EXCEPT DELAY") suggests it was just someone who can't spell.
Quote from: Kacie Jane on August 12, 2013, 05:20:50 PM
(To put it another way, say my personal average speed in ideal conditions on that section of highway were 65 mph, thus taking me 24 minutes to reach my destination. If the screen reads 26 minutes, that means traffic is light enough that I could probably still get there in 24 minutes with only a minimal amount of weaving, if any. If the screen reads 22 minutes, I'm still going to take 24 minutes to get there -- keeping to the right lane, of course. The ability to show speeds faster than the speed limit doesn't actually provide any additional usefulness when it comes to communicating congestion levels.)
to get from 26 to 24 under many circumstances would imply some weaving skills worthy of Mario Andretti. as traffic levels increase, things go away in this order:
1) the ability to consistently go at the average speed
2) the average speed itself
Quote from: deathtopumpkins on August 12, 2013, 07:10:50 PMI disagree - to me, being unable to do 5-10 over the speed limit counts as congestion.
Right. But what I'm saying is that even if it's reporting what I'm calling 0 congestion and an average speed of 60 mph, you can probably still do 5-10 over the speed limit (but probably not 15-20). If it were a rare case where the 26 meant exactly 26, then yeah, there are probably a lot of cars on the road, and there might be some of what you're calling "minor congestion" at some of the ramps, but the left lanes are probably more or less free-flowing (at least until the section between SR 520 and I-90).
Quote from: deathtopumpkins on August 12, 2013, 07:10:50 PM
The problem with your argument is that you're assuming the speed limit to be the average speed in ideal conditions, which it rarely ever is.
Not exactly, though I'm probably notorious at this point for expressing myself poorly. My argument is that this is actually a pretty silly argument, because knowing Seattle traffic, it's probably pretty unlikely that the average speed is precisely 60 mph. (If the VMS were displaying a true 26, that probably means that it's free-flowing (speed > 60) up to a certain point, with a couple of miles of < 40 mph through downtown and/or the U-district. And while Jake may be right re: Mario Andretti, I think once you get beyond 26, and not by very much, the weaving does become a non-issue.
Quote from: briantroutman on August 10, 2013, 08:44:34 PM
Maybe someone has already done this, but wouldn't it be possible to have a VMS that essentially worked like a giant e-ink screen–like you have on a Kindle? The sheeting behind could be retroreflective and require no backlighting, and since electricity is only needed to change the display, the e-ink display could be almost entirely non-powered. And of course such a screen would also be able to reproduce perfect FHWA alphabets, route shields, and diagrammatics. It would be a quantum leap ahead of our current VMSes–which are about as technically advanced as the game board on 1970s-era Family Feud.
Perhaps it's possible but just too expensive at this time.
Problem is that you want these signs to be visible from far away, which means some part of the sign needs to be lit, which means you're still using power all the time.
Quote from: Steve on August 14, 2013, 11:51:12 PM
Problem is that you want these signs to be visible from far away, which means some part of the sign needs to be lit, which means you're still using power all the time.
why is this necessary? if the background were retroreflective, then it would not be need to be lit, would it? or am I missing something here?
Quote from: agentsteel53 on August 14, 2013, 11:52:35 PM
Quote from: Steve on August 14, 2013, 11:51:12 PM
Problem is that you want these signs to be visible from far away, which means some part of the sign needs to be lit, which means you're still using power all the time.
why is this necessary? if the background were retroreflective, then it would not be need to be lit, would it? or am I missing something here?
How do you have a retroreflective background with the letters changing on it? Also, the letters themselves wouldn't be retroreflective, and nothing's harder to read than black letters on a reflective background (ask NY and CT button copy).
Quote from: Steve on August 15, 2013, 11:54:12 PM
Quote from: agentsteel53 on August 14, 2013, 11:52:35 PM
Quote from: Steve on August 14, 2013, 11:51:12 PM
Problem is that you want these signs to be visible from far away, which means some part of the sign needs to be lit, which means you're still using power all the time.
why is this necessary? if the background were retroreflective, then it would not be need to be lit, would it? or am I missing something here?
How do you have a retroreflective background with the letters changing on it? Also, the letters themselves wouldn't be retroreflective, and nothing's harder to read than black letters on a reflective background (ask NY and CT button copy).
The problem with NY and CT button copy, as I understand it – also a problem in Ohio sometimes – is that the letters are supposed to be white, but they're not as reflective as they're supposed to be, making them relatively dark. Meanwhile, the background is very reflective, but it's supposed to be a dark color. And the result is a poorly-reflective white against a too-reflective dark color, which turns out to be nearly the same brightness and thus there's not enough contrast to read the sign. A sign that literally has black legend on a retroreflective (light-colored or white) background works quite well.
The talk in this thread about having a reflective background comes from the misconception that "e-ink" technology works like an LCD, where there's a static background which is selectively darkened by changing foreground elements. E-ink doesn't work that way. A giant LCD panel with a retroreflective background could work, but due to the polarizing nature of LCD displays, you cut the reflected light by at least half even in the parts of the display that are supposed to be white. As for e-ink, that's really very similar to the Family Feud display described above, but the individual elements are microscopic, and many of these elements are addressed by the same logical pixel, even on high-density e-ink displays. I think incorporating retroreflectivity into this technology would be difficult – and unnecessary.
A VMS probably doesn't need pixels smaller than an inch; at 4 dots per inch, you could fairly accurately reproduce the FHWA fonts. Manufacturing rotating pixels that are a retroreflective light color on one side and black on the other shouldn't be too hard. Actually, I think there are one or two older VMS in Columbus that use technology like this, with pixels about 1 to 2 inch in size. I suspect the expense of this display type would be significantly more for smaller pixels, possibly just because manufacturers aren't currently making them. Columbus's newer VMS have light-emitting pixels (probably LEDs) at 1 inch or smaller, and I think it's a safe assumption that this was determined the most cost-effective technology to meet ODOT's needs at the time.
Quote from: Steve on August 15, 2013, 11:54:12 PM
How do you have a retroreflective background with the letters changing on it? Also, the letters themselves wouldn't be retroreflective, and nothing's harder to read than black letters on a reflective background (ask NY and CT button copy).
Quote from: vtk on August 16, 2013, 12:29:21 AM
The talk in this thread about having a reflective background comes from the misconception that "e-ink" technology works like an LCD...
OK perhaps I am mixing up a few technologies. Upon further review, I see that the e-ink particles have a light side and a dark side, and those sides are alternately charged (positive or negative). So changing the charge of the matrix behind the screen causes the particle to flip–dark or light depending on the polarity. That isn't exactly what I had envisioned.
I remember hearing about a similar but slightly different technology where rather than flipping heads or tails, the pixels would stand on end when a positive charge was applied–thereby allowing light to pass through–or lay flat and block the light when a negative charge was applied–sort of like a million microscopic shutters. In this case, a solid retroreflective sheet could be behind the pixel layer, acting almost exactly like any other retroreflective signage–just with pixels blocking the light instead of pigment.
If I recall correctly, like e-ink, this technology only needed to power applied to redraw the display. In either case, the low power requirements would merely be a side benefit. I think the primary advantage would be having a VMS that looked and behaved more like regular signage–not glowing at you like a scoreboard or TV screen.
Quote from: thenetwork on October 26, 2012, 12:28:01 AM
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
I'm not sure I remember those signs in Michigan but I do remember these. These were everywhere in SE Michigan until about 10 - 11 years ago and didn't seem to be much better than the signs you mentioned:
https://goo.gl/maps/a2JESgvKgNvUSwXM8
https://goo.gl/maps/qsDU1UBvLPCmyMY79
https://goo.gl/maps/ao3zvqH9PB51cWQW7
https://goo.gl/maps/D6cS1kt2D6m3bX5c6
https://goo.gl/maps/81ewD3uDGPa4dFYJ7
https://goo.gl/maps/9jz1nNBgQDcA6GiMA
https://goo.gl/maps/daADPkQ7MDsxp997A
As you see in the photos, there are a number of pixels stuck "on" or "off" and didn't have a ton of backlighting to stand out.
Quote from: ztonyg on April 07, 2021, 11:12:14 PM
Quote from: thenetwork on October 26, 2012, 12:28:01 AM
The WORST of Changeable Message Signs was -- bar none -- the ones that M-DOT placed over many of the freeways in and around Downtown Detroit in the late 80's/early 90's:
They were all Black-on-Gray LCD signs -- imagine your local digital gas-pump readouts in an enlarged dot-,...er triangle/square-matrix format that was nearly unreadable with-or-without lighting, day or night. And even if you could read the text, most of the time there was usually a section which was stuck in an on-or-off position.
Worst.Sign.Technology.Ever.
I'm not sure I remember those signs in Michigan but I do remember these. These were everywhere in SE Michigan until about 10 - 11 years ago and didn't seem to be much better than the signs you mentioned:
https://goo.gl/maps/a2JESgvKgNvUSwXM8
https://goo.gl/maps/qsDU1UBvLPCmyMY79
https://goo.gl/maps/ao3zvqH9PB51cWQW7
https://goo.gl/maps/D6cS1kt2D6m3bX5c6
https://goo.gl/maps/81ewD3uDGPa4dFYJ7
https://goo.gl/maps/9jz1nNBgQDcA6GiMA
https://goo.gl/maps/daADPkQ7MDsxp997A
As you see in the photos, there are a number of pixels stuck "on" or "off" and didn't have a ton of backlighting to stand out.
Prior to those, weren't there LCD message boards around metro Detroit?
Black-On-Gray alpha-numeric characters are fine on a gas pump or digital watch, but on a huge overhead gantry,....