As a kid, living in Ohio in the 70's, there used to be speed limit signs on state highways (mostly on rural stretches) that would read a different speed limit, depending on the time of day.
For example, these "Magic Signs" could read 55 for the speed limit in the daytime, and 50 at night. If you watched the sign at night, you could sometimes see the sign change from 50 to 55 right before you passed it.
ISTR the Ohio State Driver's Handbooks/Rules would have an example of this type of sign in the common road signs section.
1) Anybody remember this type of sign?
2) Was it just limited to Ohio?
3) How did they put the "magic" in these signs?
4) When were they eliminated? (It sounds like, despite it being a unique little innovation, it was ultimately pooh-poohed by ASHTA).
I know Florida used them, and I think there was one in place just over the border in the early 2000s.
http://www.alpsroads.net/roads/fl/i-95/sl.jpg (http://www.alpsroads.net/roads/fl/i-95/sl.jpg) Alps' Roads dislikes hotlinking.
here's an example from Michael Summa. (the photo is from 1982, but the sign is at least 8 years older ... speed limits above 55 were abolished in 1973-74)
Washington State used them too. A friend was able to get a copy of the sign detail drawing from WSDOT for me a few years ago.
I don't remember them in Ohio, but back then, we always crossed Ohio in the daytime.
But, how did this type of sign work? What was the "magic?"
Quote from: agentsteel53 on June 28, 2010, 10:36:05 PM
I know Florida used them, and I think there was one in place just over the border in the early 2000s.
Currently in the locations where the night speed limit is lower than the day speed limit (Big Pine Key along US1 comes to mind), the day limit is non-reflective so in the dark all that shows up is the night limit (white on black). I don't know if I'd call that magic however...
Quote from: mightyace on June 29, 2010, 01:51:29 PM
But, how did this type of sign work? What was the "magic?"
in the daytime, white shows up as white, while black shows up as black.
at night, retroreflective shows up as white, while non-retroreflective shows up as black.
so, through judicious use of four different combinations, including non-reflective white and retroreflective black, you can make a sign with two entirely different messages depending on whether it's day or night.
I would imagine the easiest way to do this is with two screens - first, screen-print non-reflective black, on non-reflective white. Then, using a second design, screen-print glass-bead ink over the result, thereby setting the retroreflective bit.
I feel like this could be a good idea on interstate highways in the city. If cities or states feel the necessity to have a 55 MPH speed limit, couldn't we at least limit it to rush hour. Then during non-rush hour times there could be a 60 or 65 MPH speed limit.
Quote from: wh15395 on June 29, 2010, 09:32:13 PM
I feel like this could be a good idea on interstate highways in the city. If cities or states feel the necessity to have a 55 MPH speed limit, couldn't we at least limit it to rush hour. Then during non-rush hour times there could be a 60 or 65 MPH speed limit.
Why? If I'm not standing still during my rush hour commute, I'm going 70-75 mph anyway.
Quote from: Brandon on June 30, 2010, 10:48:39 AM
Quote from: wh15395 on June 29, 2010, 09:32:13 PM
I feel like this could be a good idea on interstate highways in the city. If cities or states feel the necessity to have a 55 MPH speed limit, couldn't we at least limit it to rush hour. Then during non-rush hour times there could be a 60 or 65 MPH speed limit.
Why? If I'm not standing still during my rush hour commute, I'm going 70-75 mph anyway.
True, but I was just saying that because the reason for the low speed limits is because of heavy traffic. I agree that it should be at least 65MPH all the time, probably higher.
[Fixed quoting mishap. -S.]
A number of miles on I-90 outside Seattle uses them.
Michigan used them as well before the 55mph speed limits went into effect in 1974.
Georgia used to have them up until the mid 70's
Quote from: JREwing78 on July 10, 2010, 11:56:46 PM
Michigan used them as well before the 55mph speed limits went into effect in 1974.
From what everyone has said, it looks like most of the old ones died in 1974 with the 55mph limit.
Boy do I !!!
I have the old Florida tech. drawings to make those "reversible day/night" speed limit signs, and have made a few myself. As stated, a combination of non-reflective white for the night speed and reflective black (it reflects white at night.) I would love to obtain one or two of the originals from the pre 55 days. But only Mike and a few others have any.
N. Carolina, Georgia, Tennessee, Ohio, Florida used them (S. Carolina might have used them). Other states used the more usual black "NIGHT" tab under the std. day speed sign with the day speed on a non-reflective white background.
I love what "Thenetwork" said "For example, these "Magic Signs" could read 55 for the speed limit in the daytime, and 50 at night. If you watched the sign at night, you could sometimes see the sign change from 50 to 55 right before you passed it." I remember those times as a kid, too, when we would drive to Florida for Christmas Vacation and notice the same thing. As for AASHTO, who cares what they think. The signs worked very well. There is no innovation in traffic engineering any more because of associations like AASHTO, ITE (which I'm a member,) etc. only for the "so called” sake of complete uniformity! I'm so glad that I'm not the only one who noticed those reversible speed limit signs, and revered them! God Bless you all!
Averill; alhecht@comcast.net
PS I make these at home using the spec. from the states. I make full size and miniatures.
Before 1974, the signs in Michigan would read 65 m.p.h. in the daytime and 55 m.p.h. at night. :coffee:
Doesn't Texas still use these on Interstates? I thought these were what I saw on I-40 last week, with 70 during the day and 65 at night. Since I went thru there during daylight this trip I couldn't tell if the black night portion were retro-reflective or not.
Quote from: N9JIG on October 15, 2010, 08:20:38 AM
Doesn't Texas still use these on Interstates? I thought these were what I saw on I-40 last week, with 70 during the day and 65 at night. Since I went thru there during daylight this trip I couldn't tell if the black night portion were retro-reflective or not.
no, the magic signs are a single sign with a single number field, as opposed to separate day and night numbers.
I offhand do not remember if the day speed limit signs are retroreflective in Texas.
I think I saw one on I-70 WB between Colfax and C-470 in Denver before. I don't know if it is still there or not.
The NJ Turnpike has signs that uses Vane Type tech for display.
http://en.wikipedia.org/wiki/Vane_display
Do not know if this is 100% the same, but they do change it depending on traffic
Quote from: Zmapper on October 17, 2010, 10:21:17 PM
I think I saw one on I-70 WB between Colfax and C-470 in Denver before. I don't know if it is still there or not.
You might be referring to the 2-year-old LED variable speed limit signs that were installed in that area (all the way west to Vail on I-70). Heck of a lot easier to read than the earlier generation variable speed limit signs which used light bulbs behind day-glo flippy elements.
Quote from: agentsteel53 on October 15, 2010, 11:29:54 AM
Quote from: N9JIG on October 15, 2010, 08:20:38 AM
Doesn't Texas still use these on Interstates? I thought these were what I saw on I-40 last week, with 70 during the day and 65 at night. Since I went thru there during daylight this trip I couldn't tell if the black night portion were retro-reflective or not.
no, the magic signs are a single sign with a single number field, as opposed to separate day and night numbers.
I offhand do not remember if the day speed limit signs are retroreflective in Texas.
NO. Back before the 55 Texas used "exposed glass beads" spread on the white paint "SPEED LIMIT" top portion of the sign, and plain white paint were the "70" was placed, so the day speed would not show at night. Below was placed the std. white text on a black background. The two sign concept. Averill alhecht@comcast.net
Someone on E-Bay is selling an old Missouri 65 sign that looks like it has this magic combination. I just don't have the money right now. Plus I have made some of these myself! If you're interested type "highway signs" and scroll until you find it.
One of my parents told me about those signs once. Apparently vandals sometimes bent the signposts to funny angles, somehow making the day.speed limit display at night.
Retroreflective black sounds like an oxymoron, but it's actually charcoal gray, not black. The vans I drive at work have their numbers in retroreflective charcoal gray; the rest of the van is of course nonreflective white. At certain headlight distances, this combination is unreadible because the retroreflected dark gray is the same brightness as the diffused white.
I made a night time rendering of Mike Sumas's speed limit sign as it would look at night, I will try to post the picture on here somehow, if someone knows how to do it, please write. Averill :confused:
Quote from: averill on December 26, 2011, 10:36:09 PM
I made a night time rendering of Mike Sumas's speed limit sign as it would look at night, I will try to post the picture on here somehow, if someone knows how to do it, please write. Averill :confused:
Post it online somewhere first (Imgur (http://imgur.com) is pretty simple to use). Then, click "Reply", click (https://www.aaroads.com/forum/Themes/Button_Copy/images/bbc/img.gif), and place the link to the image between the tags that button creates.
I saw these in Utah in the 1960s while traveling with my parents. Seems to me in looking through the 1948 MUTCD, where the modern era of road signage was introduced, that referenced this type of sign as one of two acceptable means of posting night speed limits (the other being the white on black night limit sign paired with a non-reflective daytime limit.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FtCvgZ.jpg&hash=940d3f57c1a00c52d10def2869efdac8ec61d229)
This is my rendering of what the day/night speed limit sign looks like using black reflective sheeting. I have made a few of these myself, both miniature and full size. I remember them and loved them. I hope to get a used one someday.
Quote from: The High Plains Traveler on December 30, 2011, 01:25:23 PM
I saw these in Utah in the 1960s while traveling with my parents. Seems to me in looking through the 1948 MUTCD, where the modern era of road signage was introduced, that referenced this type of sign as one of two acceptable means of posting night speed limits (the other being the white on black night limit sign paired with a non-reflective daytime limit.
I think this practice was in the MUTCD until almost the 2000 edition. I have all of them and I know it is in the 78 MUTCD.
I saw a photo once of an Arizona speed limit sign from the early 40s with white text on a black background spelling out "SPEED LIMIT 60" - but with the glass cateyes spelling out "SPEED LIMIT 50" instead.
The wave of the future, electronic speed limit signs that could adjust for road conditions?
Quote from: texaskdog on February 16, 2012, 12:33:17 PM
The wave of the future, electronic speed limit signs that could adjust for road conditions?
Wave of the present in a lot of metropolitan areas. The New Jersey Turnpike has had them for decades.
Always amazed how a speed limit in rush hour or at night is the same as a wide open highway.
Quote from: texaskdog on February 16, 2012, 12:33:17 PM
The wave of the future, electronic speed limit signs that could adjust for road conditions?
We had those on part of the Beltway for about two years beginning in July 2008, but they were removed. People ignored the varied speed limit as much as, maybe more than, they ignore the normal one.
When I picture variable speed limit signs I always think of Rosco P. Coltrane hitting the button to flip over the panel on that sign to change it from 35 to 15 or whatever.
Quote from: 1995hoo on February 18, 2012, 10:10:33 AM
When I picture variable speed limit signs I always think of Rosco P. Coltrane hitting the button to flip over the panel on that sign to change it from 35 to 15 or whatever.
Rosco P. Coltrane from The Dukes of Hazzard for those that aren't familiar with that name.
Loved the TV show... :-D
Hated the Movie... :angry:
Quote from: 1995hoo on February 18, 2012, 10:10:33 AM
Quote from: texaskdog on February 16, 2012, 12:33:17 PM
The wave of the future, electronic speed limit signs that could adjust for road conditions?
We had those on part of the Beltway for about two years beginning in July 2008, but they were removed. People ignored the varied speed limit as much as, maybe more than, they ignore the normal one.
When I picture variable speed limit signs I always think of Rosco P. Coltrane hitting the button to flip over the panel on that sign to change it from 35 to 15 or whatever.
Yeah, and he'd always demonstrate it in Boss Hogg's office and the thing would go haywire, causing immense winds inside the office.
I watched that show every chance I got, even though I think my parents feared it would teach me to disrespect real life police.
Quote from: vtk on November 03, 2011, 11:28:05 PM
One of my parents told me about those signs once. Apparently vandals sometimes bent the signposts to funny angles, somehow making the day.speed limit display at night.
Retroreflective black sounds like an oxymoron, but it's actually charcoal gray, not black. The vans I drive at work have their numbers in retroreflective charcoal gray; the rest of the van is of course nonreflective white. At certain headlight distances, this combination is unreadible because the retroreflected dark gray is the same brightness as the diffused white.
I appreciate you telling us how the black reflective sheeting can be reflective. In this case charcoal Gray could be used on the newer, higher reflective sheeting in the same way by just adjusting the amount of grey to keep the black appearance during the day, but making them more invisible at night.
Does it change with temperature? The picture looked like it was that kind of magic haha There are signs that resemble that here but they're LED signs so not quite the same type of magic...