ASSESSING ENVIRONMENTAL CAPACITY OF HETEROGENEOUS TRAFFIC ON URBAN ROADS: A CASE STUDY OF OGIDI-OKOLOWO ROAD

Authors

  • Abdulrahman Jimoh Alabi Department of Civil Engineering, Kwara State University, Malete. Nigeria
  • Biliyamin, A. Ibitoye Department of Civil Engineering, Kwara State University, Malete. Nigeria
  • Mariam, Funmilayo Daudu Department of Civil Engineering, Kwara State University, Malete. Nigeria
  • Mohammed Abdulkareem Adisa Department of Civil Engineering, Kwara State University, Malete. Nigeria
  • Habeeb Abdulganiyu Department of Civil Engineering, Faculty of Engineering and Technology, Kwara State University, Malete, Nigeria.
  • Nurudeen Alajagusi Department of Civil Engineering, Faculty of Engineering and Technology, Kwara State University, Malete, Nigeria.

Keywords:

Traffic flow, vehicle composition, heterogeneous traffic, emission factor, environmental capacity, urban roads.

Abstract

The study presents a comprehensive characterization and impact resistance evaluation of Nigerian-grown Ekki (Lophira alata) timber in both solid and glue-laminated (glulam) forms for application as railway sleepers. Urban roads in developing cities frequently operate under heterogeneous traffic conditions, leading to severe congestion and significant environmental degradation. This study evaluates the environmental capacity of Ogidi–Okolowo Road in Ilorin, Kwara State, Nigeria, by examining the interplay between mixed traffic characteristics and air quality impacts. Traffic flow and vehicle composition were assessed using drone-based video recording and manual counts during morning peak hours. Emission factors for CO, NOx, PM₂.₅, and HC were determined through field measurements with a Testo 310 Flue Gas Analyzer, while air quality was monitored across three distinct road segments. Environmental capacity was calculated by comparing observed peak-hour traffic volumes (in PCU/hr) and pollutant concentrations against NESREA and WHO standards.Results show that tricycles and motorcycles dominate the traffic stream (nearly 47%), with peak-hour volumes reaching 6,200 PCU/hr. The Oloje Market (3,146 PCU/hr) and Ogidi Axis (2,950 PCU/hr) sections exceeded the environmental capacity threshold of 2,500 PCU/hr, resulting in unhealthy air quality levels of PM₂.₅, PM₁₀, CO, and NO₂. Heavy vehicles, though fewer, contributed disproportionately to NOx and PM emissions. The study concludes that current traffic operations on major segments of the corridor are environmentally unsustainable. It recommends targeted traffic management measures, dedicated lanes for para-transit modes, roadside activity regulation, and stricter vehicle emission enforcement. This research provides a practical framework for assessing and improving environmental capacity in heterogeneous urban traffic environments typical of developing cities

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Published

2026-05-10

Issue

Vol. 3 No. 2 (2026): Advanced Journal of Engineering and Scientific Applications (AJESA) Volume 3 No. 2,  March/April 2026

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