UC Berkeley

This dissertation aims to increase the understanding of supply- and demand-side congestion management strategies. In particular, the work focuses on left-turn bans and congestion pricing. It proves the existence of an optimal spatiotemporal zone within which to ban left turns during the morning rush in cities with central business districts. The optimal ban is capable of reducing vehicle hours travelled significantly. Contrary to popular assumptions, left-turn bans are also capable of reducing vehicle miles traveled. The effectiveness of turn prohibitions is impacted by the distribution of origins and destinations, route lengths and time of day. Moreover, this dissertation explores the effects of combining turn prohibitions with different types of congestion pricing strategies. For the case of Stockholm, simulations show that combining cordon-based congestion pricing with the optimal portion left-turn ban creates a win-win scenario. Either additional travel time benefits are gained at the original toll levels; or the original benefits are maintained at reduced toll levels. Combining the two measures also highlights the importance of optimizing left-turn bans since banning turns in wholesale fashion does not improve Stockholm’s travel conditions. Furthermore, combining turn prohibitions with distance-based congestion pricing for a case study of downtown LA creates synergistic benefits. The reductions in travel costs due to the joint deployment of both strategies is greater than the sum of the reduction due to each strategy on its own. Adding turn prohibitions to a priced network allows commuters to arrive to their destinations both faster and closer to their desired arrival time.