- During a typical excavation operation, there is a high risk of inadvertently damaging the existing subsurface utilities. Such incidents cause significant financial loss to the project and can delay or abruptly halt ongoing construction. In many cases, they also pose a life threat and often result in accidental deaths. As a result, constructors are required to protect utility systems during excavation operations. In this paper, the applicability of advanced visualization and tracking technologies to improve work safety during urban construction projects by enhancing the visual perception of construction equipment operators is discussed. The integration of Augmented Reality (AR) visualization and the Global Positioning System (GPS) is explored to create real time views of an excavation site in which CAD models of the underground utilities can be accurately superimposed over live video streams of the real world with the resulting views being displayed to the equipment operator in real time. Copyright ASCE 2009.