Amongst studies dealing with regional and smaller zoning, this proposal calls up a spatiotemporal and multiscalar analysis in order to estimate Nord - Pas de Calais region and its labour pools (one of the way French statistical institute defines zoning) cohesiveness. Main goal pursued is therefore to reveal potential functioning and/or splintering generated by public transport, at several scales. A modelling approach of mass-transit networks permits to provide scheduled accessibility measures. Relevant indicators are used and improved to fit each studied scale. At last, provided results are analysed regarding regional transport policy main goals.