Integration of Roadside Friction with Road Geometry and Land Use: An Empirical Case Study of Taiwo Road, Ilorin, Nigeria

This study examined how roadside friction interacts with road geometry and land use to influence traffic performance on Taiwo Road, Ilorin, Nigeria. Video observations and manual traffic counts were undertaken at four road sections over 672 observation intervals during peak periods. Parked vehicles, pedestrians, street vendors and double parking were analysed using descriptive statistics, correlation analysis and Poisson regression. Friction varied spatially with roadside activity and land use, while shoulder width and curved alignment influenced the severity of its operational effects. Pedestrian presence was negatively associated with vehicle volume (β = −0.0039, p = .002; Cohen’s d = 0.245), whereas street-vendor presence was positively associated with volume (β = 0.0054, p = .005; d = 0.219). Field comparisons indicated that double parking reduced effective lane width from 3.5 m to 2.0 m or less, coinciding with a 28.6% reduction in mean operating speed (35 to 25 km/h) and an estimated 30–40% increase in travel delay. None of the individual friction variables significantly predicted lane-changing frequency. The results indicate that roadside friction should be managed as a spatially clustered and compound operational problem. The study recommends coordinated land-use management, parking control, pedestrian facilities, regulated vending and geometry-sensitive traffic management.