48 Transportation Research Record: Journal of the Transportation Research Board, No. 2579, Transportation Research Board, Washington, D.C., 2016, pp. 48–58. DOI: 10.3141/2579-06 A ﬁeld investigation was conducted with two testing devices, the min- iaturized pressuremeter test (MPMT) and a lightweight deﬂectometer (LWD), to evaluate the elastic characteristics of granular pavement layers. The stress–strain data from the MPMT tests were used to deter- mine the stiffness of pavement materials under the inﬂuence of static loading conditions in initial elastic modulus (E i ) and reload elastic modu- lus (E r ). The time–deﬂection data from the LWD tests were used to deter- mine the stiffness parameters of pavement materials under the inﬂuence of dynamic loading conditions in dynamic deformation modulus (E d ) and LWD plate deﬂection. The results of the MPMT tests were compared with the results of the LWD tests in two phases. First, a direct approach was conducted with statistical analysis. MPMT elastic moduli were com- pared with LWD dynamic moduli. The results indicate that E i and E r could be used to estimate E d . The initial-modulus model had the best pre- diction for granular pavement dynamic moduli, followed by the reload moduli model. Second, an inverse approach was achieved by implement- ing ﬁnite element analysis. Three MPMT modulus models were utilized as inputs in the two-dimensional ﬁnite element simulation to pre- dict pavement layer deﬂections. The predicted deﬂections were com- pared with deﬂections measured from LWD tests. The results revealed that a strain-level model in numerical simulation of base course moduli provided satisfactory values of predicted deﬂection and that the reload modulus model yielded the best prediction deﬂections for subgrade soils. Modern pavement design methodologies depend on mechanistic- based models that incorporate the nonlinear behavior of unbound pavement materials in dynamic modulus to simulate the response of pavement structure to expected wheel loadings. The predicted pave- ment responses (i.e., stresses, strains, and deformations) are then utilized to compute incremental pavement distresses over time. The importance of nonlinear soil characteristics in recent pavement design procedures has moved highway agencies toward nondestructive ﬁeld measurements that can emulate the effect of heavy trafﬁc loads. The lightweight deﬂectometer (LWD) was developed to operate as a quality control tool for evaluating the structural performance of pavement layers. The LWD is a nondestructive testing device that is used to measure the in situ stiffness properties of unbound pave- ment materials under the inﬂuence of dynamic impact loads. This device provides a single dynamic stiffness backcalculated on the basis of acceleration of the impulse load propagated inside a pave- ment layer. The depth of the evaluated pavement layer varies from 1.5 to 2.0 times the diameter of the LWD loading plate (1–3). This paper presents an exhaustive review of publications on employing the LWD in pavement assessment as well as the general theoreti- cal relations between LWD dynamic stiffness and measurements of other laboratory and ﬁeld tests. Experimental work was conducted by Hossain and Apeagyei (4) to study the possibility of employing the LWD as a ﬁeld-testing method to evaluate unbound granular materials for Virginia’s roads instead of conventional density and moisture content tests. It was observed that the soil modulus obtained from the LWD increases with increasing density. In addition, the study found a signiﬁcant effect of moisture content on decreasing LWD stiffness. This behav- ior may be attributed to high pore water pressure that develops when a soil is subjected to a high dynamic impact load during the LWD testing procedure. Louay et al. (5) performed a comparative study between a ﬁeld LWD test and a laboratory triaxial test to predict the laboratory resil- ient moduli of subgrades for in situ soil moduli. The results of the analysis were presented in two models. The ﬁrst model relates sub- grade resilient modulus (M r ) with LWD soil modulus (E LWD ). The sta- tistical coefﬁcients obtained from the model, including the coefﬁcient of determination (R 2 ) and root mean square error (RMSE) were .54 and 9.66 MPa, respectively. The resulting equation is = × M E r 27.75 (1) LWD 0.18 Because of the weak correlation, several physical properties of the soils that were tested were included in multivariable statistical analy- sis. This process resulted in a regression model with a better correla- tion (R 2 = .7 MPa; RMSE = 7 MPa). This model predicts the resilient modulus of subgrades in dynamic LWD soil modulus and moisture content (w): M E w r ( ) = + +       11.23 12.64 242.32 1 (2) LWD 0.2 A comparative investigation between the LWD and the falling weight deﬂectometer (FWD) was carried out by Fleming et al. (6). The authors reported that no signiﬁcant correlation exists between FWD Comparative Analyses of Granular Pavement Moduli Measured from Lightweight Deﬂectometer and Miniaturized Pressuremeter Tests Alaa M. Shaban and Paul J. Cosentino Department of Civil Engineering, College of Engineering, Florida Institute of Tech- nology, 150 West University Boulevard, Melbourne, FL 32901. Corresponding author: A. M. Shaban, ashaban2012@my.ﬁt.edu.