Route Choice Behaviour on the Nairobi Expressway, Kenya:

A Mixed-Methods Analysis of Urban Toll Road Use

Abstract

This study examined determinants of route choice behaviour on the Nairobi Expressway, Kenya’s first major urban toll road operating alongside free alternative routes. Despite growing investment in African urban toll roads, limited empirical evidence exists on motorists’ route choice behaviour in dual-network contexts. Guided by transport behaviour theory, the study assessed the influence of toll cost, entry/exit convenience, traffic flow, time savings, and road condition on motorists’ decisions. A mixed-methods cross-sectional design combined questionnaire surveys (n = 690) with five key informant interviews involving Kenya National Highways Authority and Moja Expressway Company officials. Quantitative data were analysed using descriptive statistics, correlations, and multiple linear regression, while qualitative findings were analysed thematically. The regression model was statistically significant (R² = 0.081). Traffic flow and road condition significantly influenced route choice, while toll cost, time savings, and entry/exit convenience were not significant predictors. Findings suggest motorists prioritise operational reliability and infrastructure quality over direct monetary cost.