Traffic loading is usually characterized by means of the number of Equivalent Single Axle Loads (ESALs) or by means of the axle load distributions (load spectra).The objective of this paper is to evaluate the difference on pavement response and performance when the two approaches are applied separately,and then evaluate traffic load quantification methodology.Most current pavement design methods account for expected traffic loading by converting all traffic axle configurations and loads into ESALs; some most recent methods make use of the full traffic information and estimate the pavement response and incremental damage caused by each axle load and configuration.Then,a linear sum of damage ratios (Miners law) is utilized to estimate pavement performance.Five pavement structures were evaluated under corresponding expected traffic loading.For each of these five cases,both approaches were utilized:ESALs and load spectra.Based on different Load Equivalency Factor (LEF) and Truck Load Factor (TLF),the conversion results between actual traffic load and ESALs are different.Pavement performance was evaluated applying some of the criteria proposed by the forthcoming design guide.