These Videos show "Follow the Greens" in Action


Towards more Automation

Many pilots know „Follow the Greens“ as a guidance system operational at LHR. At Heathrow the system is operated in a manual mode meaning that lights are switched on manually by a lighting panel operator up in the tower according to the clearances given by controllers. Increasingly „Follow the Greens“ is referring to a more automated system, though, in which the switching of lights or segments of the lighting system is automatically carried out by a software system.

For pilots the effect is the same – seamless, unambiguous, individual guidance by  taxiway centerline lights. For an airport operator the discussion becomes a very different one with automated “Follow the Greens”: whereas a dynamic airfield ground lighting system is required as in the past, the need is now for another software engine, often referred to as surface manager (SMAN) instead of employing shifts of lighting panel operators.

Focussing on the Needs of Controllers

ATRiCS Advanced Traffic Solutions GmbH, Germany has been one of the very early driving forces of “Follow the Greens”. Not being for the airfield lighting industry the company for a long time has advocated a more operations oriented approach to Follow the Greens focussing on the needs and work flows of controllers rather than approaching the system from an electrical engineer’s perspective.

„We have seen far too many controllers up in towers fed up with static, unintuitive button/switch interfaces that have originally been designed by electrical engineers. Our feeling was that from about 2005 onwards, this era has definitely been over and has prepared the ground for approaches putting the controller and his work in the center of attention when it comes to designing such a system.“

says ATRiCS CEO, Wolfgang Hatzack.

Interested? Get in touch! +49 761 5918 680 or visit

In Depth

“Follow-the-Greens” is an operational procedure that provides unambiguous guidance to individual pilots and drivers on the ground by dynamically switched taxiway centerline lights along their assigned taxi route.
Depending on the technical capabilities of the airfield ground lighting system this procedure also involves the control of aircraft and vehicles by using visual aids to ensure spacing.


Avoiding the „Sea of Lights“


Historically, the main reason for introducing “Follow the Greens” was to avoid safety incidents caused by disoriented pilots and drivers during night time and in low visibility conditions at major airports with a complex layout. In most cases such incidents resulted from misleading information signs, confusion by lights at night („sea of lights“) and misunderstandings of taxi clearances.
Due to the massive increase of controller workload associated with manually operating the lighting system a lot of research projects focused on the technical aspects of automatically switching taxiway centerline lights using input from the surveillance system. While technically feasible, for a long time the lack of operational flexibility and a substantial loss of situational awareness for the controllers prohibited “Follow the Greens” at complex airports with high traffic levels.


2012 – a Milestone in ATM History

A technology breakthrough was achieved in a research project funded by the German government in 2012 when ATRiCS, a company with a strong background in Artificial Intelligence, demonstrated that the benefits of “Follow the Greens” are not just limited to safety in low visibility conditions with reduced traffic levels,
but unfold in particular in good visibility conditions and high traffic density situation across the key performance areas safety, capacity, efficiency and environmental sustainability.

The Concepts are adopted by the Industry

The key for this success was the use of ATRiCS‘ TowerPad® technology, an integrated controller working position (ICWP) in combination with a backend Surface Manager (SMAN) for which the company received CANSO/Jane‘s ATC Innovation Award in 2012.
The TowerPad® combined all relevant functions for surveillance, routing, guidance and control in one single screen and introduced new concepts such as ad-hoc routing, bounded indication, floating spacing and intention-based gesture control. Not surprisingly, the new concepts have been copied many times since then.

Confirmation of Results

The initial results have been confirmed by SESAR when the TowerPad® technology was used in large scale validation exercises by Frankfurt airport (VP-649 in 2013) and Munich airport (VP-759 in 2015). A few months later, while SESAR was using some other technology to research “Follow the Greens” with a vehicle at Riga airport (VP-761 in 2016 ), TowerPad® was already in regular operations at Dubai (DXB).
When it encountered its very first day of low visibility operations on January 23th, 2016, it allowed the controllers to achieve a movement rate 62% above the declared capacity.