of the same ethnic group within firms. This paper presents empirical proof of the phenomenon and analyses the incentives …

dynamic equilibrium model of congestion, which captures various dimensions of heterogeneity: heterogeneity in preference for … carpooling, "ratio heterogeneity" between the values of time and the values of schedule delay, and "proportional heterogeneity … increasing the degree of "ratio heterogeneity", the relative efficiency of the second-best subsidization first increases and then …