The highway was opened in the s and paved in the s. It has also caused massive environmental damage and socio-economic impacts. In some areas it is poorly maintained.
Construction was started in by President Juscelino Kubitschek. The road would be used to transport cassiterite to industries in the east, and to open the west for settlement.
Comparison to imagery showed accelerating clearance, expected to increase further when the highway was paved. An inspection of the section between Porto Velho and Pimenta Bueno in September found forest clearing roads at right angles to the highway about 4 kilometres 2. In a government-planned colonisation project the immigrant farmer would be sold a hectares acres lot for agriculture or pasture with about metres 1, ft of road frontage.
Narrow strips of primary forest were left at the back of the lots. The farmer would start clearing at the access road, then clear further back to reach soil that had not yet been depleted of nutrients. Half a million settlers had moved west on BR by including ranchers, wildcat miners, land speculators and sex workers. The situation was out of control. Under this program BR was to be paved, the road network in the region expanded, colonisation schemes created or expanded, land titles regularised and economic activities encouraged.
Paving of BR through Rondonia was completed in and the number of migrants rose to about , per year. The World Bank loan had been contingent on measures being taken to protect the environment and indigenous people, but it was clear by late that these rules were being ignored and protected areas were being deforested by ranchers and small farmers.
