There are many traffic operation software packages which are used to simulate and evaluate the traffic operation process. These programs use the HCM methodology as a base in their analysis. It was noticed that there were great differences between their results when they were used in evaluating the same case study. Three packages were selected to be investigated in this study; they included SYNCHRO 7, HCS2000 and SIDRA INTERSECTION 5.1. The main objective of this study is to investigate the main causes of these differences as well as defining one of these programs to be the most representative of traffic movement on intersections and develop it. To achieve this goal, three signalized intersections were selected. The analysis of results included four main subjects; the first subject included a comparison between different investigated packages outputs and HCM methodology. The second subject included a comparison between delay times measured from the field and the corresponding delay times determined using the selected programs. The third subject included calibrating the selected software programs. Finally, evaluation to real delay times at various study cases and their corresponding values determined using the selected software packages are conducted. It can be concluded that there are significant differences between the field measured delay times and the corresponding calculated delay times using the selected software programs. It is concluded that SIDRA INTERSECTION 5.1 software after its calibration is considered the best software for predicting the field delay times at signalized intersection