Editing Variable-message sign

{{Short description|Electronic traffic sign with changeable messages}}
{{more citations needed|date=May 2015}}
[[File:MN Changeable Message Sign.jpg|thumb|[[Dot-matrix display|LED matrix]] sign over [[Interstate 94|I-94]] in [[Saint Paul, Minnesota]], advising of a road blockage during a winter storm]]
[[File:New Jersey Turnpike Reduce Speed sign.jpg|thumb|Early style of VMS on the [[New Jersey Turnpike]] using [[Neon sign|neon tubes]], since replaced by new LED VMS signs. It is next to a vane variable speed-limit sign]]
[[File:Verkehrsleitsystem Nuernberg 1.JPG|thumb|Europe's largest Dynamic Route Guidance System [[Nuremberg]], Germany]]
[[File:Illinois Tollway - Digital Signage (45706130121).jpg|thumb|[[LED display|LED]] sign over [[Interstate 90 in Illinois|I-90]] (Jane Addams Memorial Tollway) in [[Riley Township, Illinois]], showing remaining travel times]]
[[File:MÚK Lahovice, směrové tabule před odbočením na Lochkov.jpg|thumb|Mechanical variable-message sign (right) on the [[D0 motorway (Czech Republic)|Prague Ringway]], Czech Republic; made by Značky Praha s.r.o.]]
A '''variable-''' (also '''changeable-''',<ref>{{Cite web |url=http://epg.modot.org/index.php?title=616.3_Changeable_Message_Signs_%28CMS%29 |title=616.3 Changeable Message Signs (CMS) - Engineering Policy Guide<!-- Bot generated title --> |access-date=2007-12-24 |archive-date=2012-03-11 |archive-url=https://web.archive.org/web/20120311183139/http://epg.modot.org/index.php?title=616.3_Changeable_Message_Signs_%28CMS%29 |url-status=dead }}</ref> '''electronic-''', or '''dynamic-''') '''message sign''' or '''message board''', often abbreviated '''VMS''', '''VMB''', '''CMS''', or '''DMS''', and in the UK known as a '''matrix sign''',<ref>
{{citation |url=http://www.opsi.gov.uk/si/si1994/Uksi_19941519_en_2.htm#mdiv36|title=The Traffic Signs Regulations and General Directions 1994|publisher=[[Office of Public Sector Information]]|year=1994|access-date=2008-04-05}}</ref>
is an electronic [[traffic sign]] often used on [[road]]ways to give travelers information about special events. Such signs warn of [[traffic congestion]], [[traffic safety|accidents]], incidents such as terrorist attacks, [[AMBER Alert|AMBER]]/[[Silver Alert|Silver]]/[[National Blue Alert Act of 2013|Blue]] Alerts, [[construction|roadwork zones]], or [[speed limit]]s on a specific highway segment. In [[urban area]]s, VMS are used within [[parking guidance and information]] systems to guide drivers to available car parking spaces. They may also ask vehicles to take alternative routes, limit travel speed, warn of duration and location of the incidents, inform of the traffic conditions, or display general public safety messages.

==History==
{{expand section|date=May 2015}}
VMS systems were deployed at least as early as the 1950s on the [[New Jersey Turnpike]].<ref>{{Cite web|url=http://www.roadsbridges.com/amped-traffic-signs-imminent-nj-expressways|title = Amped-up traffic signs imminent for NJ expressways}}</ref> The road's signs of that period, and up to around 2012, were capable of displaying a few messages in neon, all oriented around warning drivers to slow down: "REDUCE SPEED", followed by a warning of either construction, accident, congestion, ice, snow, or fog at a certain distance ahead.<ref>{{Cite web |url=http://www.nj.gov/turnpike/documents/VMS_Guide_031912.pdf |title=Archived copy |access-date=2016-06-01 |archive-date=2015-09-10 |archive-url=https://web.archive.org/web/20150910232933/http://nj.gov/turnpike/documents/VMS_Guide_031912.pdf |url-status=dead }}</ref> The New Jersey Turnpike Authority replaced those signs (along with 1990s-vintage dot-matrix VMS systems along the [[Garden State Parkway]]) with more flexible electronic signs between 2010 and 2016.

The current VMS systems are largely deployed on [[freeway]]s, trunk highways, or in work zones.{{citation needed|date=May 2015}}

On the interchange of [[Interstate 5 in California|I-5]] and [[California State Route 120|SR 120]] in [[San Joaquin County]], California, an automated visibility and speed warning system was installed in 1996 to warn traffic of reduced visibility due to fog (where [[tule fog]] is a common problem in the winter), and of slow or stopped traffic.

Message Signs were deployed in [[Ontario]] during the 1990s and are now being upgraded on [[400-series highways]] as well as two pilot secondary highways in northeastern Ontario.<ref>{{Cite web|url=https://toronto.citynews.ca/2015/01/20/new-ontario-electronic-highway-signs-bilingual-easy-to-read/|title = New Ontario electronic highway signs bilingual, easy to read - CityNews Toronto}}</ref>

==Technologies and types==
Early variable message signs included static signs with words that would illuminate (often using neon tubing) indicating the type of incident that occurred, or signs that used rotating prisms ([[trilon]]s) to change the message being displayed. These were later replaced by dot matrix displays typically using [[eggcrate display|eggcrate]], [[fiber optic display|fiber optic]], or [[flip-disc display|flip-disc]] technology, which were capable of displaying a much wider range of messages than earlier static variable message signs. Since the late 1990s, the most common technology used in new installations for variable message signs are [[LED display]]s. In recent years, some newer LED variable message signs have the ability to display colored text and graphics.

Dot-matrix variable message signs are divided into three subgroups: character matrix, row matrix, and full matrix. In a character matrix VMS, each character is given its own matrix with equal horizontal spacing between them, typically with two or three rows of characters. In a full matrix VMS, the entire sign is a single large dot matrix display, allowing the display of different fonts and graphics. A row matrix VMS is a hybrid of the two types, divided into two or three rows like a character matrix display, except each row is a single long dot matrix display instead of being split per character horizontally.

Overhead variable message signs are today available in three form factors: front access, rear access, and walk-in. In a front access variable message sign, maintenance is performed by lifting the sign open from the front. Most smaller VMS are of the front access form factor, and are typically installed today on major arterials. The rear access form factor is similar to the front access form factor, except that maintenance is performed from the rear of the sign, and are commonly used for medium-sized dynamic message signs installed along the roadside of freeways (instead of overhead). The walk-in form factor is a more recent introduction, where maintenance on the sign is performed from the inside of the sign. A key advantage of the walk-in form factor is that lane closures are generally not required to perform maintenance on the sign. Most of the largest VMS units installed today are walk-in units, and are typically installed overhead on freeways. {{citation needed|date=March 2024}}

The NJ Turnpike Authority counts five unique types of variable message signs under its jurisdiction, at least one of which has been replaced by newer signs.<ref>{{Cite web |url=http://www.nj.gov/turnpike/documents/VMS_Guide_031912.pdf |title=Archived copy |access-date=2016-06-01 |archive-date=2015-09-10 |archive-url=https://web.archive.org/web/20150910232933/http://nj.gov/turnpike/documents/VMS_Guide_031912.pdf |url-status=dead }}</ref> They are:

#"REDUCE SPEED" neon signs (1950s-2010, obsolete, have now been replaced).
#"Changeable message signs" (trilon/ rotating-drum signs that can be used for closing roads or moving traffic to other roadways).
#Electronic VMS: signs with remotely controlled messages displayed on them; the messages are sent from the State Traffic Management Center, updating the signs automatically.
#Variable speed limit signs - used for varying the posted speed limits within work zones and in emergencies.
#Portable VMS: movable "electronic VMS". A portable VMS has much the same characteristics as a fixed electronic VMS, but can be moved from location to location as the need dictates.

==Usage==
[[File:Variable message sign.jpg|alt=Variable Message Sign|thumb|A variable-message sign.]]
Early models required an operator to be physically present when programming a message, whereas newer models may be reprogrammed remotely via a wired or wireless network or cellphone connection.{{citation needed|date=May 2015}}

A complete message on a panel generally includes a problem statement indicating incident, roadwork, stalled vehicle etc.; a location statement indicating where the incident is located; an effect statement indicating lane closure, delay, etc. and an action statement giving suggestion what to do traffic conditions ahead. These signs are also used for [[Amber alert]] messages, and in some states, [[Silver Alert|Silver]] and [[National Blue Alert Act of 2013|Blue]] Alert messages.

In some places, VMSes are set up with permanent, semi-static displays indicating predicted travel times to important traffic destinations such as major cities or interchanges along the route of a highway.

Typical messages provide the following information:

*Promotional messages about services provided by a road authority during non-critical hours, such as [[carpool]]ing efforts, [[travelers' information station]]s and [[5-1-1]] lines
*Crashes, including vehicle spin-out or rollover
*Road Works
*Incidents affecting normal traffic flow in a lane or on shoulders
*Non-recurring congestion, often a residual effect of cleared crash
*Closures of an entire road, e.g. over a mountain pass in winter.
*Exit ramp closures
*[[road debris|Debris on roadway]]
*Vehicle fires
*Wildfires
*Short-term maintenance or construction lasting less than three days
*Pavement failure alerts
*[[Amber alert|AMBER]], [[Silver Alert|Silver]], and [[National Blue Alert Act of 2013|Blue Alert]]s, as well as weather warnings via the warning infrastructure of [[NOAA Weather Radio All Hazards|NOAA Weather Radio]]'s [[Specific Area Message Encoding|SAME]] system
*Travel times
*Variable [[speed limit]]s
*Car park occupancy levels
*[[speed sign]], for recommending a speed to approach the next traffic light in its green phase.

The information comes from a variety of traffic monitoring and surveillance systems. It is expected that by providing real-time information on special events on the oncoming road, VMS can improve motorists' route selection, reduce travel time, mitigate the severity and duration of incidents and improve the performance of the transportation network.

===United Kingdom===
<gallery mode="packed" heights="100" caption="Examples of variable message signs in the UK">
File:UK traffic sign 6001.jpg|Temporary advisory speed limit of 50 mph.
File:UK traffic sign 6006.10.jpg|End of temporary restrictions.
File:UK traffic sign 6006.5.jpg|Lane 2 is closed ahead.
File:UK traffic sign 6006.1.jpg|Lane 2 and 3 are closed ahead.
File:UK traffic sign 6006.3.jpg|Lane 1 is closed ahead.
File:UK traffic sign 6006.7.jpg|Lane 1 is closed ahead.
File:UK traffic sign 6003.jpg|Leave the motorway at the next junction.
File:UK traffic sign 6006.4.jpg|Both lanes are closed.*
File:UK traffic sign 6006.2.jpg|All three lanes are closed.*
File:UK traffic sign 6006.6.jpg|All 4 lanes  are closed.*
File:UK traffic sign 6006.8.jpg|Risk of ice ahead.
File:UK traffic sign 6006.9.jpg|Risk of Fog ahead
File:UK traffic sign 6031.1.jpg|Do not use the lane below the signal.
</gallery>
<nowiki>*</nowiki> Do not enter the motorway when the red lamps are flashing in pairs from side to side.

On 27 March 1972, the first motorway computer-controlled warning lights in the UK, with 59 miles on the M6 from [[Broughton, Lancashire]] to [[Barthomley]], on the Cheshire boundary, and 26 miles on the M62 east of Whitefield, was switched on by [[Michael Heseltine]] and [[Baron Grey of Codnor|Charles Legh Shuldham Cornwall-Legh, 5th Baron Grey of Codnor]] at the headquarters of [[Cheshire Constabulary]] on Nuns Road.<ref>''Birmingham Daily Post'' Tuesday 28 March 1972, page 7</ref><ref>''Chester Chronicle'' Thursday 30 March 1972, page 2</ref>

It was centred at a police computer centre at [[Westhoughton]], that connected to police stations in Preston and Chester. The Chester site was soon be connected to the M53 and M57.<ref>''Cheshire Observer'' Friday 31 March 1972, page 21</ref> Four other regional computer centres would be opened at Perry Barr near the M6, [[Scratchwood]] near the M1, at [[Hook, Hart|Hook]] near the M3, and at [[Almondsbury]] near the M4. Most British motorways would be covered by 1975. The system was designed by GEC and had taken five years to design.<ref>''Times'' Tuesday March 28 1972, page 5</ref>

==Safety messages for drivers==
Increasingly, signs have been used to remind drivers to buckle seat belts ("Click it or ticket"), obey the speed limit, and stay off the road if impaired ("Drive sober or get pulled over").<ref name="NPR">{{cite news |last1=Kasler |first1=Karen |title=Driven to distraction: New rules recommend states steer clear of highway sign humor |url=https://www.npr.org/2024/01/19/1225370260/driven-to-distraction-new-rules-limit-those-humorous-state-highway-signs |access-date=31 October 2024 |work=NPR |date=January 19, 2024}}</ref> In a federal study, a slight majority of drivers reported that [[public safety]] messages on dynamic message signs impacted their driving behaviors.<ref>{{cite news |title=Public Perception of Safety Messages and Public Service Announcements on Dynamic Message Signs in Rural Areas |url=https://ops.fhwa.dot.gov/publications/fhwahop16048/exsum.htm |access-date=31 October 2024 |work=Federal Highway Administration |agency=US DOT |date=April 13, 2020}}</ref>

The [[Ohio]] [[Department of Transportation]] began using humorous dynamic message signs in 2015, perplexing some drivers.<ref name="NPR" /> 
Examples<ref name="NPR" /><ref>{{cite news |title=NYS DOT Gets in the Halloween Spirit |url=https://hudsonvalleycountry.com/nys-dot-halloween-signs/ |access-date=31 October 2024 |work=Hudson Valley Country |date=October 31, 2024}}</ref><ref>{{cite news |last1=Lytle |first1=Emily |title=Who is behind the pun-filled, often holiday-themed safety messages on Delaware highways? |url=https://www.delawareonline.com/story/news/local/2022/12/06/delaware-traffic-signs-meet-the-man-writing-them-i95-route-1-deldot/69688841007/ |access-date=31 October 2024 |work=Delaware Online |date=December 6, 2022}}</ref><ref>{{cite news |title=DelDOT channeling humor to drive home serious message |url=https://6abc.com/post/deldot-traffic-signs-funny-scott-neidert/15182697/ |access-date=31 October 2024 |work=6ABC Action News |date=August 13, 2024}}</ref><ref name="AP">{{cite news |title=No joke: Feds discourage humorous electronic messages on highways |url=https://apnews.com/article/ban-humorous-messages-electronic-highway-signs-3c7b0d11475d2b255f7edd197af771cc |access-date=31 October 2024 |work=Associated Press |date=January 19, 2024}}</ref><ref>{{cite news |last1=Frau |first1=Lucas |title=Funny digital highway signs will soon be banned. Here are some of our favorites from NJ |url=https://www.northjersey.com/story/news/transportation/2024/01/19/federal-highway-administration-nj-electric-signs-ban/72272497007/ |access-date=31 October 2024 |work=North Jersey.com |date=January 19, 2024}}</ref><ref>{{cite news |title=Despite new federal standards, Minnesota says funny and quirky traffic signs are here to stay |url=https://www.kktv.com/2024/01/21/despite-new-federal-standards-minnesota-says-funny-quirky-traffic-signs-are-here-stay/ |access-date=1 November 2024 |work=KARE via CNN Newsource |date=January 21, 2024}}</ref> of humorous signs seen in [[New Jersey]], [[Arizona]], [[Texas]], [[Pennsylvania]], [[Delaware]], [[Iowa]], [[New York (state)|New York]], [[Minnesota]] and [[Ohio]] include:
*"Hold on to your butts. Help prevent forest fires."
*"We'll be blunt. Don't drive high." 
*"Visiting in-laws? Slow down, get there late."
*"Only sparklers should be lit." and “Don’t drive Star Spangled hammered."(for [[Fourth of July]])
*"Hocus pocus – drive with focus." and "Slow down in work zones - my mummy works here." (for [[Halloween]])
*"Drive Drunk and YULE be sorry." and “You’re not a Christmas tree. Don’t drive lit." 
*"HO HO HO, please drive slow." and "Don't be a grinch, let them merge."
*"Reckless drivers are worse than fruitcake." 
*"Only Rudolph should be lit." and "Santa's watching, put down the phone."
*“I’m just a sign asking drivers to use turn signals.”
*“Seatbelts always pass a vibe check.”
*“Come on, Eileen… your speed is obscene."
*“May the 4th be with you, text I will not.”
*"Irish you would slow down."
*"I saw the sign and it opened up my eyes."
*"Nice car, did it come with a turn signal?" and "Get your head out of your apps."
*"100 is the temperature - not the speed limit."
*“Let’s go Barbie, Buckle Up. Yes. You Ken!” and “Fast & Furious? Nope! Slow & Cautious.”

In 2024, concerns that these messages were distracting drivers led the Federal Highway Administration to strongly discourage signs with "obscure meanings, references to pop culture" or humor.<ref name="AP" />

==Movable versions==
{{unreferenced section|date=July 2016}}
[[File:Cromwell_road_outside_VA.jpg|thumb|Trailer-mounted VMS in central London, England]]
Truck-mounted VMSes (also called Portable Changeable Message Signs or PCMS) are sometimes dispatched by highway agencies such as [[Caltrans]] to warn traffic of incidents such as accidents in areas where permanent VMSes are not available or near enough as a preventive measure for reducing secondary accidents. They are often deployed in pairs so that the second VMS truck can take over when the traffic queue overtakes the first truck, requiring the first truck to reposition further upstream from the queue, to be effective. An optional third truck, the team leader, may be utilized for driving by and monitoring the incident itself, traffic patterns and delay times, to make strategic decisions for minimizing delays—analogous to spotter planes used in fighting forest fires.

Trailer-mounted variable-message signs are used to alter traffic patterns near work zones, and for traffic management for special events, natural disasters, and other temporary traffic patterns. The messages displayed on the sign can be programmed locally on the unit's control panel, or units equipped with a cellular modem can be programmed remotely via computer or phone. Most manufacturers produce trailers which comply with the [[National Transportation Communications for Intelligent Transportation System Protocol]] (NTCIP) which allows the portable trailer to be integrated with an [[intelligent transportation system]]. Trailer-mounted VMS can be equipped with radar, cameras, and other sensing devices as part of a [[smart work zone]] deployment..

==In popular culture==
A variable-message sign figures significantly into the plot of the 1991 film ''[[L.A. Story]]''.

==Gallery==
<gallery mode="packed" heights="150px">
Display Sign on CKE.jpg|A single row matrix LED sign on [[E03 expressway (Sri Lanka)|Katunayake Expressway]] in [[Colombo]], Sri Lanka
Avoid London (2005-07-07).jpg|A three row fixed character matrix LED sign warns "Avoid London - Area Closed - Turn On Radio" following the [[7 July 2005 London bombings]]
Verkehrsleitsystem Nuernberg 2.JPG|Europe's largest Dynamic Route Guidance System, in [[Nuremberg]], Germany (hybrid rotating prism and row matrix LED)
NBTPL-Variable-Board.jpg|A dual row matrix LED sign on [[National Highway 4 (India, old numbering)|National Highway 4]], in Bangalore, India
VBA A4.jpg|A row matrix LED sign on an [[Interchange (road)|interchange]] of a German [[Autobahn]] with side graphics display.
Highway 401 digital message sign.jpg|A full matrix sign on Highway 401 in [[Ontario]], Canada.
Variable message sign with travel times on I-70 West, north of Evergreen, CO.jpg|A full matrix walk-in cabinet LED sign (manufactured by Skyline Products) displaying travel times on [[Interstate 70 in Colorado|Interstate 70]] north of [[Evergreen, Colorado|Evergreen]], [[Colorado]], USA.
Road Safety Road Sign.jpg|A dual row matrix LED sign in [[Manhattan]] reminding motorists to drive safely.
2013-12-28 15 01 10 New variable message sign on northbound Interstate 95 (New Jersey Turnpike) just north of Exit 7A (Interstate 195, Trenton, Shore Points) in Robbinsville Township, Mercer County, New Jersey.jpg|A [[Daktronics]] rear access color LED sign on the [[New Jersey Turnpike]], USA, displaying a warning about congestion ahead.
Smart highway signs on Interstate 90 in Mercer Island, Washington.jpg|A set of LED signs on [[Interstate 90 in Washington|Interstate 90]] in [[Mercer Island, Washington]], USA, that warn of an upcoming lane closure due to a collision. Normally, these signs display variable speed limits that are adjusted during rush hour.
日高自動車道 日高富川IC付近.jpg|A variable-message sign tells drivers that a section of the [[Hidaka Expressway]] in [[Hokkaido]], Japan is damaged after the [[2018 Hokkaido Eastern Iburi earthquake]].
COVID-19 NC highway notice.jpg|A sign in [[Winston-Salem, North Carolina]], USA, displaying the website for information on [[COVID-19 pandemic|COVID-19]] in [[North Carolina]].
SouthernExpresswayClosed.jpg|Main South Road at the northern end of the [[Southern Expressway (Australia)|Southern Expressway]], Adelaide, Australia, during morning peak (looking south), closed to southbound traffic. This has now changed.
File:20230402 Taiwan's Changeable Message Sign.png|Variable message sign at the Changzhi Interchange in Taiwan
File:Variable message sign graphical.jpg|Fully graphical variable message sign reminding motorists to reduce speed during rain in [[North–South Expressway (Malaysia)|North-South Expressway]], Perak, Malaysia
</gallery>

==See also==
* [[Flip-disc display]]
* [[gantry (transport)]]
* [[Glossary of road transport terms]]
* [[Passenger information system]]
* [[Radar speed sign]]

==References==
{{Reflist}}

==External links==
{{Commons category|Variable-message road signs}}
* ''[https://tmcpfs.ops.fhwa.dot.gov/cfprojects/uploaded_files/CMS%20Operation%20and%20Messaging%20Handbook-Final%20Draft.pdf Changeable Message Sign Operation and Messaging Handbook]''. Operations Office of Travel Management, [[Federal Highway Administration]], August 2004. Retrieved 2009-12-07.
* [https://mutcd.fhwa.dot.gov/pdfs/2009r1r2/part2ithu2n.pdf Chapter 2L: Changeable Message Signs]. U.S. [[Manual on Uniform Traffic Control Devices]], 2009 ed. with Revisions 1 and 2.

{{traffic signs}}
{{Authority control}}

[[Category:Traffic signs]]
[[Category:Intelligent transportation system sensor]]
[[Category:Digital media]]