The majority of his work in Latin America has been in Colombia. At the Escuela Colombiana de Medicina in Bogotá, Colombia, he served as an instructor of family medicine and area community medicine and as a field data collector for a study examining socio-economic process and health. He was also a physician in Cerro Norte Health Center in Bogotá. Villaveces is also a research associate at the Instituto Cisalva at the Universidad del Valle, Cali, Colombia. He has experience researching issues related to firearm-related violence in Latin America. One study examined the effect of homicide rates after a ban on carrying firearms was issued in two Colombian cities. He has also investigated child delinquency and the prophylaxis of crime in early twentieth century Latin America. In Cali, Colombia, he currently conducts research to establish the association of built environment characteristics with fatal and non-fatal pedestrian injuries. He currently has collaborations on occupational injuries with the Federal University of Bahia in Brazil. He has also taught injury prevention courses in Mexico, Vietnam, Uganda, Ghana, and Switzerland. For the Pan-American Health Organization, wrote an advocacy document on Safe and Healthy Transportation and reviewed and edited a course for youth violence prevention to be implemented in six Latin-American countries. He has also served as consultant for the United Nations Development Fund, World Health Organization, Transport Research Lab, UK, and the Centre for Humanitarian Dialogue in Geneva, Switzerland.