Les temps de transport pour délimiter des aires urbaines fonctionnelles ?

Abstract

This paper is a methodological contribution to the harmonized delineation of potential functional urban areas in Europe, based on a temporal framework that uses isochrones and an accessibility criteria to the city-center. From the case of three major metropolis (Paris, Barcelona, Berlin), isochron lines are constructed by referring to road transport times data at peak times (Navstreets database). They are first confronted with the functional perimeters of urban areas which are more classically based on commuter flows. Secondly, different methods of estimating road congestion are compared to real traffic speeds, in order to test the possibility of speed modelling in the absence of detailed data about transport times. We show that the use of a gradient of congestion allows to substantially improve the modelling of accessibility areas, compared to the use of theoretical speeds : the differences with accessibility areas based on Navstreets data are reduced by 30 %, in terms of area. Lastly we suggest a few thoughts for improving this method and extend it to other European cities.

Keywords

• functional urban areas
• isochrones
• road accessibility
• urban database
• harmonization
• Europe