For pilots and drivers in ITS (intelligent transportation system), the high density of information
in driving environments with advanced technology generates some requests for workload evaluation
techniques. In this paper, four typical subjective mentalworkload evaluation techniques are reviewed. With
the four methods, the evaluation calculations on the data of experiments in three different driving
environments are made. The calculated results are compared by sensitivity analysis aswell as the subjective
evaluation of participants, and the regression functions ofRNASA-TLX indexes forthe three different driving
environments are set up.