Highway Research Record

Critical Assessment of Signal Phasing of Cycle Time: A case study on Delhi

Duration:January 2004 to June 2004
School of Planning and Architecture, New Delhi (R)

Scope and Objective
(i) To review the literature related to traffic signal operation, phasing and sequencing for different types of intersections and      to study the other concepts related to the research topic.
(ii) To study the existing phasing and sequencing pattern of different types of selected intersections in Delhi urban area.
(iii) To study the sequencing of phases as well as cycle time with regard to delay, queue and capacity of selected       intersections.
(iv) To evolve and suggest a phasing sequence which gives reduced delay and improved capacity of signalized intersection.
(v) The study is limited to 3& 4 arm fixed time isolated intersection in Delhi urban area(which constitutes 90% of signalized       intersection)
(vi) Intersection with traffic volume less than 8000 PCU/hr has been selected which have the scope for optimization in terms       of delay and performance

Extensive study was carried out to review the studies related to intersection typology, important terms (signal design), signal phasing, delay models. Secondary data like intersection type, intersection inventory data, signal phasing typology existing in Delhi were collected and analyzed for grouping of different intersections of different typologies. Primary data was collected at selected intersection like classified traffic volume count at an interval of 15-min for different phases, classified traffic volume count an interval of 6 sec for different phases. The data was critically analyzed to develop the final recommendations and conclusions.

Findings and Conclusions
(i) Delay experienced by the vehicular traffic in respect of arm-wise sequence is minimum as compared to other types of     sequences of phases.
(ii) The estimated capacity based on observed saturation flow with respect to arm-wise traffic movement worked out to be      the highest as compared to other types of sequence of phases.
(iii) The sequence of early cut-off operation does not ensure any benefit when traffic flows from all the intersections are in      equal proportion.
(iv) It is observed that there is increase in delay of operation of this sequence with the equal proportion of traffic as compared      to other types of sequence of phases.

Mohd. Nadeem, “Critical Assessment of Signal Phasing of Cycle Time , Case study- Delhi”, Master’s Thesis (unpublished), Department of Transport Planning, School of Planning and Architecture, New Delhi, 2004