The effect on equilibrium trip assignment of different link congestion functions

Abstract Recent applications of equilibrium trip assignment to moderate and large-sized networks have shown that link flows are sensitive to the function used to express link congestion. In this paper, the effect of different link congestion functions on equilibrium assignment is examined for a large regional highway network. Resulting equilibrium assignment flows are compared with each other and with observed traffic counts to evaluate the congestion functions' performance. Implications for the use of equilibrium assignment by Metropolitan Planning Organizations are discussed.