Institute of Transportation Studies at UC Berkeley

This paper presents a departure-time user equilibrium model that explicitly considers the most important determinants of congestion behavior in cities during the morning commute: different commuter origins, merge interactions and queue spillovers. The proposed model combines three previous works: the departure-time equilibrium theory in Vickrey (1969), the traffic flow model of Newell (1993) and the merge theory in Daganzo (1996). The paper examines the simplest possible network exhibiting the three important features and discusses the ensuing policy implications. The solution algorithm can be used as a building block for equilibrium analysis of more complex, singledestination networks with departure-time choice. The results reveal unexpected situations where ramp-metering can be beneficial, and others where the provision of more freeway storage can be counterproductive.