The accuracy of cell-based dynamic traffic assignment: Impact of signal control on system optimality

T. Islam, H. L. Vu, M. Panda, N. Hoang, D. Ngoduy

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther


Dynamic Traffic Assignment (DTA) provides an approach to determine the optimal path and/or departure time based on the transportation network characteristics and user behavior (e.g., selfish or social). In the literature, most of the contributions study DTA problems without including traffic signal control in the framework. The few contributions that report signal control models are either mixed-integer or non-linear formulations and computationally intractable. The only continuous linear signal control method presented in the literature is the Cycle-length Same as Discrete Time-interval (CSDT) control scheme. This model entails trade-off between cycle-length and cell-length. Furthermore, this approach compromises accuracy and usability of the solutions. In this study, we propose a novel signal control model namely, Signal Control with Realistic Cyclelength (SCRC) which overcomes the trade-off between cycle-length and cell-length and strikes a balance between complexity and accuracy. The underlying idea of this model is to use a different time scale for the cycle-length. This time scale can be set to any multiple of the time slot of the Dynamic Network Loading (DNL) model (e.g. CTM, TTM, and LTM) and enables us to set realistic lengths for the signal control cycles. Results show, the SCRC model not only attains accuracy comparable to the CSDT model but also more resilient against extreme traffic conditions. Furthermore, the presented approach substantially reduces computational complexity and can attain solution faster.

Original languageEnglish
Title of host publicationProceedings of the 20th International Conference of Hong Kong Society for Transportation Studies, HKSTS 2015
Subtitle of host publicationUrban Transport Analytics
PublisherHong Kong Society for Transportation Studies Limited
Number of pages8
ISBN (Electronic)9789881581440
Publication statusPublished - 2015
Externally publishedYes
EventInternational Conference of Hong Kong Society for Transportation Studies (HKSTS) 2015 - Hong Kong, Hong Kong
Duration: 12 Dec 201514 Dec 2015
Conference number: 20th


ConferenceInternational Conference of Hong Kong Society for Transportation Studies (HKSTS) 2015
Abbreviated titleHKSTS 2015
CountryHong Kong
CityHong Kong


  • Dynamic Traffic Assignment (DTA)
  • Linear formulation
  • Optimization
  • Traffic signal control

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