The ATM 1 system is generally considered to be one of the safest transport systems in the world. It is used
by, and is certainly visible to, most of the western world. However, it is being subjected to considerable change
due to the expectations of its stakeholders in terms of cost of operation and more recently as it opens its Safety
Processes to outside attention.
This paper aims to address how ATM regulation began, what required it to change, how that change is
being accommodated, and how to prevent that change from losing the desirable features of the system.
The paper also shows how these changes have been based on the idea of quantified risk.