Evaluating Traffic Operations at an Urban Roundabout in a Development City: Evidence from Gaakanbi, Nigeria
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Date
2026-03-29
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Journal ISSN
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Publisher
International Journal of Multidisciplinary Department
Abstract
Abstract
Efficient operation of urban roundabouts is critical for managing traffic flow, particularly in
rapidly growing cities characterized by heterogeneous traffic conditions. This study evaluates the
operational performance of Gaa Akanbi Roundabout using established traffic engineering
metrics, including average control delay, queue length, and Level of Service (LOS), in
accordance with Highway Capacity Manual (HCM) standards. Field data were obtained through
direct geometric measurements and video-based traffic surveys conducted during peak periods
over seven consecutive days. Traffic volumes and turning movements were manually extracted
from recorded footage, while performance indicators such as delay and queue length were
computed using standard analytical procedures.
The results indicate that the roundabout operates at an overall average delay of 34.5 seconds per
vehicle, corresponding to LOS C, which reflects stable but moderately delayed traffic conditions.
However, significant disparities were observed across individual approaches. The western
approach exhibited the poorest performance, with a delay of 46.2 seconds per vehicle (LOS E),
indicating oversaturation largely due to limited entry capacity and inadequate geometric design.
The southern and northern approaches recorded delays of 38.5 seconds and 30.2 seconds per
vehicle, respectively, both operating at LOS D, suggesting moderate congestion with relatively
stable flow conditions. In contrast, the eastern approach demonstrated comparatively efficient
International Journal of Multidisciplinary Department
Published by: International Journal & Research Global Publisher
ISSN: 3108-2718
Article History:
Received: 09 March 2026 | Accepted: 18 March 2026 | Published: 29 March 2026
DOI: https://doi.org/10.5281/zenodo.19313415
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This article is licensed under a Creative Commons Attribution 4.0 International License.
operation, with a delay of 23.1 seconds per vehicle (LOS C), characterized by lower conflict
levels and shorter queues.