The effect of geosynthetic layers on moisture distribution and plastic deformation of paved and unpaved road sections is studied using numerical simulations. The geosynthetic layers consisted of, from top to bottom, a transport layer, a geonet, and a nonwoven geotextile (referred to as a geocomposite capillary barrier drain by previous researchers). Two geotextile types were modeled as the transport layer: woven fiberglass and nonwoven polypropylene. The numerical models were verified against published results obtained from a soil-geotextile column. Inclusion of the geosynthetic layers at the interface of the aggregate base course (ABC) and subgrade increased suction in the subgrade and decreased it in the ABC during a simulated rainfall event. The woven fiberglass geotextile led to higher suctions in the ABC compared with the nonwoven polypropylene geotextile. The geosynthetic layers decreased the plastic deformation in both paved and unpaved road sections through combined mechanistic and hydraulic actions. Increasing the thickness of the asphalt and ABC layers decreased the reinforcement effect of the geotextile while increasing its beneficial hydraulic effect in term of the suction level. In sections with a thinner asphalt layer, the woven fiberglass, functioning as a transport layer, decreased the plastic deformation of the profile by up to 20% compared with the profile with the-nonwoven polypropylene geotextile. Increasing the thickness of the asphalt layer, however, reduced this difference to approximately 4%. In unpaved sections, the inclusion of the woven fiberglass layer decreased the plastic deformation by approximately 24% more than the profile with nonwoven polypropylene geotextrile, regardless of the aggregate base course thickness used in the analysis. (C) 2013 American Society of Civil Engineers.