Determinants of Rail Transit Adoption Among Private Vehicle Users in Klang Valley, Malaysia: An Extended Theory of Planned Behaviour Analysis

Private vehicle overreliance in Klang Valley, Malaysia contributes to severe traffic congestion, air pollution, and carbon emissions, yet public transport modal shift remains far below national policy targets. This study extends the Theory of Planned Behaviour (TPB) by incorporating two external constructs, environmental concern (EC) and technology adoption (TA), to investigate the behavioural intention of 483 private vehicle users to switch to rail transit. Hypotheses were tested using partial least squares structural equation modelling (PLS-SEM). The results show that, with the exception of subjective norm (β=0.064, p=0.180), all constructs exert significant positive effects on behavioural intention. Technology adoption emerged as the strongest direct predictor (β=0.417), followed by perceived behaviour control (β=0.340). Environmental concern operated exclusively through indirect pathways, mediated by attitude and perceived behaviour control, and exhibited the largest effect size on the TPB components (f2 = 0.380–0.449, large effect).