The Effect of Modifying Double Continuous Flow Intersections Layout Geometric Features on their Operation

Ibrahim Khliefat1, *, Ahmad Deeb2, Mohammad Mubarak3, Mohammad Naser4
1 Civil Engineering Department, Al-Balqa Applied University, Salt, Jordan
2 SETS Intl. Amman, Jordan
3 General Administration of Studies and Design Traffic Studies Department, Riyadh Municipality, Riyadh, KSA
4 Civil Engineering Department, School of Engineering, The University of Jordan, Amman, Jordan

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Creative Commons License
© 2021 Khliefat et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at Department of Civil Engineering, Al-Balqa Applied University, Salt, Jordan; E-mail:



Continuous flow interventions were first introduced as an alternative to improve traffic operations in the intersections with severe congestion caused by heavy left-turn movements.


This study quantified the effect of modifying the intersection angles of Double Continuous Flow Intersections (DCFI) on their operational characteristics. Mainly, the effects of changing the intersection angle between the different approaches of the main intersection and the angle of the minor cross-over intersections were investigated.


VISSIM software simulation models were used for modifying several design features related to the DCFI and the operational performance was compared between the different simulation scenarios.

Results and Discussion:

Changes to the cross-over intersection angle increase the safety levels by providing better channelization of traffic movements on the minor intersections of the DCFI and reduce the intersection footprint to be used at high-density urban locations. Increasing the cross-over intersection angle and changing the layout geometry have adverse effects on the capacity of the conventional DCFI. This is mainly because of the added curvature in the intersection approaches which reduces the vehicle speeds, therefore reducing the overall capacity of the modified intersection when compared to the conventional DCFI. However, the total footprint for the intersection is reduced for the modified layout geometry, which improves the capacity of the DCFI.


The study has explored the effects of modifying the DCFI intersection angles to fit the limited space in major urban areas on the capacity and performance of the intersection. It showed that DCFI designs could be applied in areas with limited space availability and skewed intersection angles.

Keywords: Displaced left turn, Double continuous flow intersections, Level of service, Traffic operations, Unconventional intersection design, Vissim.