Service Credibility and Rider Retention in Sustainable Urban Bus Mobility: An Exploratory Measurement Approach Using Bus-User Data from Pakistan

Retaining bus users is a practical condition for sustainable urban mobility, but transport agencies need defensible passenger-centered measures to judge whether service experience is credible enough to support continued use. This study tests an exploratory measurement approach linking perceived bus service quality, satisfaction, perceived value, and loyalty, using urban bus-user data collected in Pakistan as the empirical setting rather than as a national-representative case. A mixed-mode survey produced 230 responses; 227 valid cases remained after pre-specified screening of ineligible and out-of-frame records. The analysis used item diagnostics, exploratory factor analysis, HC3-robust regression, bootstrapped indirect-association testing, subgroup description, and qualitative coding of open-ended responses. The retained sample was young, student-oriented, and strongly transit-dependent, so the results mainly describe regular bus users with limited modal flexibility. Service-quality items were factorable (KMO = 0.725; Bartlett’s chi-square = 851.56, df = 435, p < 0.001), but parallel analysis supported one dominant general service-quality signal rather than a stable five-dimensional SERVQUAL structure. General service quality (GSQ) is therefore treated as an empirical indicator of perceived service credibility, not as a validated new latent construct. GSQ was positively associated with satisfaction (beta = 0.382, p < 0.001), perceived value (beta = 0.389, p < 0.001), and loyalty after satisfaction and perceived value were included (beta = 0.233, p < 0.001). Bootstrap results were consistent with indirect association through satisfaction (estimate = 0.032, 95% CI [0.011, 0.057]) and perceived value (estimate = 0.035, 95% CI [0.010, 0.062]), while a residual direct association remained. Frequent riders rated reliability, responsiveness, perceived value, and loyalty more critically, but interaction testing did not confirm moderation by bus-use frequency. Open-ended comments repeatedly pointed to punctuality and passenger information, with safety also appearing as a salient threshold concern. The findings support passenger-centered sustainability monitoring by identifying service credibility, reliability, responsiveness, safety, and perceived value as practical indicators for retaining transit-dependent bus users, while ruling out any claim that the imported SERVQUAL structure was fully validated in this sample without confirmatory revalidation.