01520315

Component

Street network design and organization is a subject of much controversy: there is no consensus on what is the best option to provide the greatest level of mobility across a network. In this paper, we provide additional insights on this issue by analyzing finite square grids under three different street configurations: bidirectional streets, bidirectional streets with prohibited left turns, and unidirectional streets. Two different methodological approaches are used: analytical formulations and simulations based on a static user equilibrium traffic assignment. Analytical formulations describe the allocation of traffic flows under homogeneous congestion patterns, and reveal insights on behavior at the expense of some simplifying assumptions. Simulation techniques (with a static traffic assignment) examine the behavior under more realistic conditions; this is especially important for high traffic demand scenarios. In all the experiments the authors consider a uniform demand pattern, and compare different levels of demand and network size. The study indicates that simulations and analytical formulations provide similar results for low congested scenarios; but as the system becomes more congested, results start to differ across the two approaches. Moreover, the best urban configuration is also dependent on the congestion level. When the network is uncongested (i.e. low demands) the bidirectional streets network with prohibited left turns appears to be the best option. When the network is congested, however, the unidirectional street networks appear to provide lower travel times. This difference is mostly caused by the delay formulation employed (based on HCM-2010) that penalizes more the streets with lower saturation flows. This penalizes the bidirectional networks as compared to the unidirectional networks.

This paper was sponsored by TRB committee ADB30(10) Paper Review Group #6.

01503729

14-3962

English

18p

2014

Transportation Research Board 93rd Annual Meeting

Digital/other

Figures (8) ; References (22)

Highway design; Mathematical models; One way streets; Opposing traffic; Traffic congestion; Traffic delays; Traffic simulation; Travel demand; Travel time; Urban areas

Design; Highways; Operations and Traffic Management; I72: Traffic and Transport Planning; I73: Traffic Control

Transportation Research Board Annual Meeting 2014 Paper #14-3962

TRIS, TRB, ATRI

Jan 27 2014 3:22PM