Pavement surface roughness, one of the indicators of pavement performance, is affected by the structural stability of a pavement. Some commonly used indices of surface roughness are Present Serviceability Rating (PSR) and International Roughness Index (IRI). In the last decade, several advanced techniques were introduced to measure IRI cost-effectively and rapidly. This paper describes the use of smartphone-based technology for measuring IRI of pavements. A section of Highway Route-39 between El Carbón and Bonito Oriental in Olancho and Colón, Honduras was constructed with a mechanically stabilized aggregate base course layer. Such mechanical stabilization was achieved using a multi-axial geogrid. Mechanical stabilization contributes to preserving material stiffness for an extended service period and offers an opportunity to pavement designers to optimize pavement layers to attain the same or higher targeted pavement life. The conventional design of pavement with a layer of aggregate base over cement-treated granular subbase was replaced with a geogrid-based design without the need for cement treatment. The improved design included a layer of geogrid at the interface of aggregate base and untreated granular subbase layers. After heavy-trafficking for two years, the IRI information of the pavement was collected and evaluated to understand the effects of traffic and environmental loads.