In recent decades, one of the most widely used methods to evaluate the influence of road design on traffic safety has been road design consistency studies. To carry out these studies, it is necessary to have operating speed profiles of the road. Typically, existing operating speed models developed for other conditions, regions, or countries are used. However, speed estimation models should be developed or calibrated considering local conditions and must also undergo periodic reviews over time. The objective of this study is to develop proprietary operating speed prediction models that consider the geometric design characteristics of roads in flat and rolling terrain, as well as the conditions of the country’s vehicle fleet. The proposed methodology consists of the following stages: analysis of the country’s roads and definition of fixed parameters to be investigated, determination of sites and sample selection, speed measurements, development of prediction models, and validation of the developed models. The results of this research achieve, for the first time in Costa Rica, the development of prediction models for operating speeds on national roads with rural characteristics.