Bogota is a city with different problems; one of the most important is the high vehicular congestion, which is caused for the low capacity of the current road network, the high population density, inefficient transportation and bad driving habits. Therefore it is necessary to perform studies to model possible solutions for mobility in Bogota. The Universidad de Los Andes has a transport model for Bogota in which include three steps of the transport model of fourth steps, the step is not taken in to account is the modal selection, for that reason, this study suggest a model that can represent the behavior of the population respect to selecting a transportation mode, taking into account previous studies and the the city conditions. This study classified the transport models as public and private, in order to determine different utility functions, these functions were close to the actual user behavior, although these were some inconsistencies, due to the research did not include stated preference surveys and field studies. The functions were obtained from the survey on mobility Bogota in 2011and previous studies; these functions were adjusted to the actual behavior of the Bogota population by an iteration process. Further studies should be added new items to the functions as comfort, access time, walk time, and others; these items allow obtain functions that fit the reality in a better way, because these take into account a greater number of factors that may influence the mode that users choose.