Although different formulations have been suggested Branston, 1976, Davidson, 1966; Spiess, 1990,National Research Council, 2000, the Bureau of Public Roads' BPR Traffic Assignment Manual 1964 was chosen as it has been one of the most traditionally-used for updating transport network costs.
Aunque diferentes formulaciones han sido sugeridas Branston, 1976; Davidson, 1966; Spiess, 1990; National Research Council, 2000, se eligió la función BPR de la Bureau of Public Roads Traffic Assignment Manual; BPR, 1964, que tradicionalmente ha sido una de las más usadas para actualizar los costos sobre la red de transporte.