The study, “Amazonía en la encrucijada” (“The Amazon at the Crossroads”), by the Amazon Geo-Referenced Socio-Environmental Information Network (RAISG, by its Portuguese acronym) presents an overview of the pressure caused by roads in Brazil, Bolivia, Colombia, Ecuador, Perú and Venezuela. According to the report, of the 136,000 kilometers of roads mapped in the region, at least 26,000 are in protected natural areas and indigenous territories. For example, in the Brazilian Amazon, the report states that most deforestation occurs in the vicinity of roads. The report also suggests that this trend is increasing. You can read it at this link (in Spanish).