Despite the common belief that one-way streets are more operationally efficient due to their larger capacities, two-way street networks, especially those without left turns at intersections, can outperform one-way street networks when measuring operational performance at a network level (i.e., using total trip completion rates). However, some recent studies indicated that two-way street networks without left turns may be highly vulnerable to disruptive events inside the network. This study uses a kinematic-wave theory model to compare the performance of three network configurations – specifically, two-way, two-way without left turns, and one-way networks – under link disruptions. When road users have prior knowledge about the link disruption and can detour in advance, the two-way network with left turns performs the worst because it has the lowest capacity among the three network configurations. When road users have no prior knowledge about the link disruption and begin to detour only after approaching the disrupted link, two-way networks with and without left turns are both severely impacted. As two-way network with left turns is still constrained by its capacity, degradation in two-way network without left turns is mainly contributed to inflexibility, especially when links in the network center are disrupted. One-way networks appear to more robustly accommodate disruptions both with and without prior knowledge, compared to the other two network configurations.
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Resilience of Urban Street Network Configurations under Low Demands
Urban street networks are subject to a variety of random disruptions. The impact of movement restrictions (e.g., one-way or left-turn restrictions) on the ability of a network to overcome these disruptions—that is, its resilience—has not been thoroughly studied. To address this gap, this paper investigates the resilience of one-way and two-way square grid street networks with and without left turns under light traffic conditions. Networks are studied using a simplified routing algorithm that can be examined analytically and a microsimulation that describes detailed vehicle dynamics. In the simplified method, routing choices are enumerated for all possible origin–destination (OD) combinations to identify how the removal of a link affects operations, both when knowledge of the disruption is and is not available at the vehicle’s origin. Disruptions on two-way networks that allow left turns tend to have little impact on travel distances because of the availability of multiple shortest paths between OD pairs and the flexibility in route modification. Two-way networks that restrict left turns at intersections only have a single shortest-distance path between any OD pair and thus experience larger increases in travel distance, even when the disruption is known ahead of time. One-way networks sometimes have multiple shortest-distance routes and thus travel distances increase less than two-way network without left turns when links are disrupted. These results reveal a clear tradeoff between improved efficiency and reduced resilience for networks that have movement restrictions, and can be used as a basis to study network resilience under more congested scenarios and in more realistic network structures.
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- Award ID(s):
- 1749200
- NSF-PAR ID:
- 10219842
- Date Published:
- Journal Name:
- Transportation Research Record: Journal of the Transportation Research Board
- Volume:
- 2674
- Issue:
- 9
- ISSN:
- 0361-1981
- Page Range / eLocation ID:
- 982 to 994
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1177/0361198120933269
