title: Limits of predictability in commuting flows in the absence of data for calibration.
abstract: The estimation of commuting flows at different spatial scales is a fundamental problem for different areas of study. Many current methods rely on parameters requiring calibration from empirical trip volumes. Their values are often not generalizable to cases without calibration data. To solve this problem we develop a statistical expression to calculate commuting trips with a quantitative functional form to estimate the model parameter when empirical trip data is not available. We calculate commuting trip volumes at scales from within a city to an entire country, introducing a scaling parameter α to the recently proposed parameter free radiation model. The model requires only widely available population and facility density distributions. The parameter can be interpreted as the influence of the region scale and the degree of heterogeneity in the facility distribution. We explore in detail the scaling limitations of this problem, namely under which conditions the proposed model can be applied without trip data for calibration. On the other hand, when empirical trip data is available, we show that the proposed model's estimation accuracy is as good as other existing models. We validated the model in different regions in the U.S., then successfully applied it in three different countries.
authors.affiliation: Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Yingxiang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Applied Math, Universidad Politécnica, Madrid, 28040, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Herrera
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Eagle
authors.affiliation: 1] Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [2] Engineering Systems Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Marta C
authors.initials: MC
authors.lastname: González