There doesn't seem to be such a neat term in English for this. I understand it is simply meaning that works that meet these criteria may be executed without requiring road closure.

"All sewer works should be so positioned to allow maintenance without road closure. Manholes should be sited away from wheel tracks or areas used by ..."
www.highland.gov.uk/NR/rdonlyres/BE3109CD-EF45.../0/mudhut....

"The road remains open while work can be done without road closure, ... Traffic is being detoured on the AA Highway (KY 9). ..."
www.kypost.com/dpp/news/.../work-at-mall-road-may-


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Note added at 17 hrs (2010-12-21 11:14:26 GMT)
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Effectively, running repairs: though one would not use that expression formally in this context.

IOW, not an exceptional one. An exceptional might involve reduction/closure of services over a weekend, say, even if work has stopped for the weekend, might require that traffic be diverted, might affect traffic for longer than one week, and (guessing here), might involve "hit-and-miss" work for lengths in excess of 500m.

I really don't think you have to look for anything beyond a pretty standard meaning of courant, its "signification courante let us say!

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Note added at 13 hrs (2010-12-21 07:42:17 GMT)
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Alternat – refers to when traffic is stopped alternately in each direction:

Un ALTERNAT DE CIRCULATION pourra être imposé au droit des rétrécissements de chaussée, après une pré-signalisation par panneaux KC1 portant la mention "CIRCULATION ALTERNEE".
http://briconville.free.fr/commune/pages/arretes.html

Pour les RN en dehors des agglomération et pour les autoroutes, la circulaire du 6 février 1996 impose la réalisation d’une fiche de prévision de chantier et d’un dossier d’exploitation sous chantier dans les quelques cas où, malgré les mesures d’exploitation prévues, LE CHANTIER RISQUE D’OCCASIONNER UNE GÊNE NOTABLE AUX USAGERS. UN TEL CHANTIER EST ALORS APPELÉ NON COURANT.

LES TERMES DE CHANTIER NON COURANT ET DE CHANTIER COURANT NE FONT PAS RÉFÉRENCE À LA FRÉQUENCE DU TYPE DE CHANTIER, MAIS AU FAIT QU’ILS ENGENDRENT OU NON UNE GÊNE SENSIBLE À L’ÉCOULEMENT DU TRAFIC, ou encore, que LES DISPOSITIONS D’EXPLOITATION SONT TRÈS INHABITUELLES et demandent donc des précautions tout à fait particulières.
Selon la circulaire, un chantier est considéré comme non courant s’il répond positivement à l’un au moins des critères suivants :
• trafic prévu supérieur à la capacité résiduelle au droit du chantier,
• existence d’une réduction de la capacité habituelle pendant un jour défini comme "hors chantier" par la circulaire annuelle de la DSCR,
• alternat d’une longueur supérieure à 500 m,
• débit prévisible par voie laissée libre à la circulation supérieur à :
- 1 000 véh/h par voie de largeur supérieure ou égale à 3 m (hors alternat),
- 1 200 véh/h par voie laissé libre sur autoroute ou route interurbaine à chaussées séparées,
- 1 500 véh/h par voie laissé libre sur autoroute ou route urbaine ou périurbaine à chaussées séparées.
Des critères supplémentaires sont à prendre en compte pour les routes à chaussées séparées : ...

[ ... ]

Chantier courant UN CHANTIER EST DIT COURANT S’IL N’ENTRAÎNE PAS DE GÊNE NOTABLE POUR L’ÉCOULEMENT DU TRAFIC, notamment si la capacité résiduelle est supérieure à la demande de trafic. Des critères plus complets figurent dans la circulaire du 6 février 1996 relative à l’exploitation sous chantier.
Chantier non courant Un chantier non courant est un chantier qui ne remplit pas tous les critères de chantier courant. Cela signifie qu’il risquera d’engendrer une gêne notable ou des difficultés d’exploitation particulières. Selon la circulaire du 6 février 1996 relative à l’exploitation sous chantier, il doit faire l’objet d’un dossier d’exploitation et d’une coordination avec les autres chantiers.
http://www.sr68.fr/IMG/pdf/V6_Choix_d_un_mode_d_exploitation...

From the above it might be thought that courant / non courant refer to whether the traffic flows or not. However, even in the case of a chantier courant traffic may be stopped temporarily to allow traffic to move in the opposite direction. To me, therefore, the key is rather les dispositions d’exploitation sont TRÈS INHABITUELLES in the case of a chantier non courant, which means the steps taken to manage a chantier non courant must be (relatively) habituelles = courantes.


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Note added at 18 hrs (2010-12-21 12:00:01 GMT)
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The embargo - which will benefit shoppers heading to the Trafford Centre and the Lowry Outlet in Greater Manchester and Cheshire Oaks in Merseyside – means a start on ROUTINE MAINTENANCE WORKS, including overnight roadworks, will be put back to allow people get to the shops and away again without being inconvenienced or delayed.
ROUTINE ROADWORKS INCLUDES CARRIAGEWAY, LANE AND HARD SHOULDER CLOSURES for lighting repairs and replacement, line renewals, gulley clearance, litter picking and other work such as barrier repairs and electrical faults
Between the start of this month (Monday, November 1) and midnight on Friday, December 31, start times for routine maintenance works are being delayed for at least two hours on routes between junctions 5 and 15 of the M60, junctions 1 and 3 of the M61 and junctions 10 and 12 of the M62.
Typically, work on routine maintenance starts between 9pm and 10pm – and usually finishes at 5am – depending how busy the motorway is. However, thanks to the embargo, start times may be delayed until midnight in the run-up to Christmas
http://nds.coi.gov.uk/content/detail.aspx?NewsAreaId=2&Relea...

"Although we SUSPEND ROUTINE ROADWORKS DURING THE SUMMER, there will still be traffic management in place at MAJOR WORKS, such as the new A38 Dobwalls bypass which is due to be finished by the end of the summer and will ensure even better traffic flow through the area next summer."
http://www.highways.gov.uk/news/pressrelease.aspx?pressrelea...

All ROUTINE ROADWORKS will be suspended over the May Day Bank Holiday. There will, however, be localised closures, which will be in place at ...
gov-news.org/gov/uk/news/west_midlands.../65036.html

ROUTINE ROADWORK should only result in MINOR DELAYS for the morning commute. Temperatures should remain constant in the 70s and storms ...
www.tonganoxiemirror.com/videos/2010/jun/22/1092/

You should expect to encounter ROUTINE ROADWORK if you're headed toward Topeka or Kansas City from Lawrence today. ...
www.desotoexplorer.com/search/vertical/media.video/?...

The Kansas Department of Transportation does rOUTINE ROADWORK THAT REQUIRES TRAFFIC ON TWO-LANE HIGHWAYS TO BE NARROWED TO ONE LANE. ...
cedb.asce.org/cgi/WWWdisplay.cgi?170932
[They all this "routine roadwork" but the text indicates that it is quite different from the French definition: with one lane closed on these remote rural highways in Kansas, a pilot car is used to lead traffic through each way, apparently, which suggests that the closed portions are somewhat long. But what is "routine" in a remote part of Kansas is very different to "routine" on a busy French motorway.]

Delays expected due to temporary traffic lights and MAJOR ROADWORKS on A578 Twist Lane both ways between A579 Atherleigh Way / Parsonage Way / Findlay ...
www.leighjournal.co.uk/li/roadworks.in.Leigh

MAJOR ROADWORKS across England. THESE ROADWORKS MAY ADD MORE THAN 30 MINUTES TO YOUR JOURNEY. Check www.highways.gov.uk or call 08457 50 40 30 for the ...
www.direct.gov.uk/prod_consum_dg/groups/dg.../dg_185905.pdf