During the 1960s and 1970s, Curitiba was facing the highest urban growth rates of any city in Brazil - approximately 5% per annum. In order to assure that new population would be settled into an urban form conducive to efficient provision of city services, the City established a structural plan for Curitiba that integrated transport, housing, and land use policies. Five main transit corridors were designated heading from the city centre to the periphery. Land use legislation was reformed to encourage and permit high density residential and commercial construction along these corridors. New public housing construction was also concentrated on these corridors. Finally, a new roadway architecture was developed to create a dedicated roadway for public transit vehicles and to separate express roadways for private vehicles which led into the centre of the city flanking the dedicated public transit corridor. This integrated approach to urban development has allowed Curitiba to maintain a profitable public transit system which serves approximately 75% of the total daily commuter population.