Almost every civil engineering project involves heavy construction equipment to create earthworks. This in turn is connected with carbon dioxide emissions, which are hazardous to the environment, especially in densely populated areas. Strict control and regulation of emissions from construction equipment has already been introduced in Hong Kong. This paper presents the results of several years of field research on the performance of construction equipment (excavators). The comparative analysis concerns the data obtained during a field survey in relation to the outlays proposed in the catalogues of material outlays commonly used in Poland (KNR catalogues.) The presented problem fills in the gaps in research on the performance of construction equipment. The results of the study clearly show the discrepancy between theoretical data from the KNR and the actual use of construction equipment during the construction of underground sanitary networks. Apart from the excessive consumption of diesel fuel, sequentially increased CO2 emissions occur. The presented research results allow for the development of an innovative method for the optimal use of heavy construction equipment, thus reducing CO2 emissions. This study is a continuation of a pilot study conducted by the staff of the Institute of Civil Engineering, Warsaw University of Life Science.