Abstarct: Reducing the tunnels' pre-construction uncertainties, especially concerning the final time and cost of the tunnel can be useful in initial planning and can reduce the decision making risks to an acceptable level. DAT is a statistical method which probabilistically predicts the time and cost required for tunnel execution before the actual start of building operations. In this paper, using the DAT method and considering the pre-construction data of Hamro tunnel, the probabilistic time and construction cost of the entire tunnel was predicted. The new features presented in this study include the use of DAT method, using tunneling experts' views through questionnaire to access the input data of DAT method, indecisive application of data relevant to the tunnel input and output and boring locations, coding of Markov model in MATLAB software to execute the geological model of DAT method, using Primavera Risk Analysis software in the construction model for implementing Monte Carlo simulation. Also comparison of the time and cost obtained from DAT method using the tunnel pre-construction data and the actual costs of tunnel execution and validation of the method to be used for the future projects are among the other advantages of the proposed method. Accordingly involving the above new features in the DAT method, the obtained results indicated high similarity with the actual results, confirming the validity of DAT method for decreasing the time and final cost uncertainties in execution of future projects.