The #CodeYellow, Red, Orange

The idea came after viewing tweets relating to traffic in the Atlanta area earlier this year.  Back in January 2014, a winter storm that did less than 2 inches of snow hit that area and shut down that entire region, virtually Atlanta into a real life version of The Walking Dead.  (Ironically, that TV show is based in Atlanta, and cities in the Southern States do not have the snow removal like this area has.)  One of the traffic reporters uses a similar system although he uses different wording the colors are always red and yellow based on severity.

ADVISORY means there is no active incident but conditions are favorable for an incident to occur.  ALERT means an incident is active.

Code Orange and Code Yellow can be up for the same section of mainline – but Code Red and Code Yellow supercede each other.


The conditions for a Code Yellow includes but not limited to:

  • An incident has occurred, such as a minor accident or stalled vehicle.
  • Higher than normal risk for an incident to occur (weather, civil unrest, special events)
  • Heavier than normal congestion, but traffic is not at a standstill

Code Yellow indicates that there has been a disruption of normal traffic flow.

Mainline incidents triggering Code Yellow will expire as soon as the incident is cleared and traffic flow returns to normal.  Weather related ones (i.e. fog, rain, high wind) will expire as the conditions improve.  Occasions where the Code Yellow was caused by special events and civil unrest are a case-by-case situation and will be monitored as necessary.


Conditions for Code Orange includes

  • scheduled construction (usually announced in advance) involving lane closures
  • emergency lane closures that are construction related
  • rolling lane closures for striping or pothole patching, which may be unannounced

Code Orange is associated with road construction.  Traffic disruption can be more serious than a Code Yellow but not severe enough to trigger Code Red.  Sometimes full weekend closures may occur from construction – these are well announced.


Code Red is triggered when any of these 3 factors are present:

  • an incident has blocked all mainline lanes
  • severe traffic congestion has occurred where traffic is stopped or barely moving.
  • conditions for an incident to occur is at HIGH RISK

Code Red is much more serious, as there has been major traffic flow disruption.   In a Code Red, it is basically “all hands on deck” with the emergency crews.  Code Red is typically for incidents that have required the use of medical helicopters, fatalities, and/or triggered traffic congestion stretching several miles in length.

With a Code Red, there is a chance of secondary incidents to occur as well – these incidents are sometimes more serious than the initial incident that has occurred, and tends to happen at the location where the traffic congestion begins.  Depending on the time of the day and the severity of the incident, the emergency crews may delay a potential Code Red alert to a time window that is less likely to cause severe traffic impacts.

Severe winter storms could pull off Code Red by themselves, especially when a freezing rain event is expected to happen.


Created 11/6/2014

Last update: 12/2/2014 – clarified ALERT and ADVISORY, added a link that was omitted.  Also noted Code Red Alerts could be placed on a delay depending on incidents.


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