A reverse causal-effect modeling approach for signal control of an oversaturated intersection

Hongchao Liu, Kevin N. Balke, Wei Hua Lin

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


A novel approach is presented in which signalized intersections are treated as normal highway bottlenecks for improved computational efficiency. It is unique in two ways. First, it treats the signalized intersections as common freeway bottlenecks by a reversed cause and effect modeling approach. Both traffic arrivals and departures are modeled by smooth continuous functions of time as if there were no interruptions to traffic flows from signals. The use of smooth continuous functions for departure curves instead of commonly used step functions makes it easy to apply differential calculus in optimization and future extension to a system of intersections. Second, a dynamic linear programming (LP) model is then developed to maximize the total vehicular output from the intersection during the entire period of congestion subject to prevailing capacity and other operational constraints. The continuous optimal departure flow rate (the effect) is then converted to signal timing parameters (the cause) that can be readily implemented. Two numerical examples are presented to demonstrate the properties of the proposed algorithm and examine its performance.

Original languageEnglish
Pages (from-to)742-754
Number of pages13
JournalTransportation Research Part C: Emerging Technologies
Issue number6
StatePublished - Dec 2008


  • Optimization models
  • Traffic signals


Dive into the research topics of 'A reverse causal-effect modeling approach for signal control of an oversaturated intersection'. Together they form a unique fingerprint.

Cite this