Signal Timing Optimization for Improved Mobility and Air Quality

Signalized intersections are associated with a considerable amount of wasted time, fuel consumption, and emissions. Given the critical need to mitigate congestion and its associated externalities, several research efforts have focused on developing multi-objective signal timing optimization algorithms. However, only a few have considered both delay and emissions simultaneously and the ones that have, lack inclusion of transit vehicles or modal-based emission estimates both of which contribute towards a more realistic representation of operations and emissions in urban multimodal transportation systems. This paper develops and tests a bi-objective signal control system that minimizes a weighted combination of total vehicle delay and emissions for both autos and transit vehicles at signalized intersections. Simulation tests for a variety of auto demands, transit vehicle arrivals, and pollutants are performed. Pareto optimal solutions and the trade-offs between delay and emissions as well as their impact on transit operation for different combinations of the two objectives are presented. The results reveal that the two objectives can be conflicting or not depending on the air pollutant type considered and emission rates used for autos and transit vehicles. Implementation of the proposed signal timing optimization can be used to assist decision-makers with choosing the appropriate weights that meet their priorities.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee AHB25 Standing Committee on Traffic Signal Systems.
  • Corporate Authors:

    Transportation Research Board

  • Authors:
    • Khalighi, Farnoush
    • Christofa, Eleni
  • Conference:
  • Date: 2019


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References;
  • Pagination: 8p

Subject/Index Terms

Filing Info

  • Accession Number: 01698306
  • Record Type: Publication
  • Report/Paper Numbers: 19-05255
  • Files: TRIS, TRB, ATRI
  • Created Date: Mar 1 2019 3:51PM