Study of the Trade-off Between Efficiency and Equity in the Control of Urban Traffic Networks

Open Access
Author:
Anthony, Ryan Duschl
Area of Honors:
Civil Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Vikash Varun Gayah, Thesis Supervisor
  • Eric Todd Donnell, Honors Advisor
Keywords:
  • Traffic Congestion
  • Efficiency
  • Equity
  • Metering
  • Urban Traffic Networks
  • Traffic Control
  • Macroscopic Traffic Modeling
Abstract:
Congestion in urban traffic networks has become a recurring issue that continues to escalate to unprecedented levels of concern. Network-wide traffic control techniques offer a viable, realistic, and universally applicable solution to mitigate congestion. One particular network-wide technique to manage traffic is perimeter flow control, otherwise known as perimeter metering. Perimeter metering is effective because it is cheaper than building new infrastructure and does not require new traffic control policies. Perimeter metering is simply implemented by re-timing existing traffic signals along the perimeter of an urban network. One drawback to perimeter metering is that it is inherently inequitable. Specifically, it causes a subset of the travelers using a network to experience higher average delays than other travelers. With that inequity taken into consideration, a perimeter metering strategy still offers a viable solution to mitigate congestion as it results in a more efficient traffic network overall. This thesis explores the trade-off that exists between improving the overall efficiency of a traffic network while introducing a geographical inequity when perimeter metering strategies are incorporated into an urban traffic network. Comparison of travel times for those traveling from a suburb to the downtown with downtown only travel times revealed a non-linear relationship between the inequity and inefficiency introduced from incorporating variations of two different perimeter metering strategies. This thesis discusses the assumptions, traffic dynamics, and metering strategies in detail. Finally, it compares this trade-off using measures such as elasticity to understand ways in which a perimeter metering strategy could be applicable within an urban traffic network.