Assessing the Effect of Client–Consultant–Contractor Relationships on Quality Assurance in Road Construction: Evidence from the Dar es Salaam Metropolitan Development Project, Tanzania

Ensuring quality assurance in road construction remains a persistent challenge in Tanzania, largely due to fragmented collaboration and communication among key stakeholders, namely the client, consultant, and contractor. Despite the critical role these actors play in achieving quality infrastructure outcomes, limited empirical evidence exists on how their relational dynamics influence project quality. This study examined the effects of the client, consultant, and contractor relationship, specifically communication, meetings, and reporting, on quality assurance in road construction projects. A case study design was adopted, employing a quantitative approach, with data collected from 122 randomly selected stakeholders involved in 50 road projects under the Dar es Salaam Metropolitan Development Project. Factor analysis was conducted to validate constructs, retaining only variables with factor loadings ≥ 0.600. Multiple regression analysis revealed that communication and reporting are significant predictors of quality assurance, explaining 91.1% of the variance (R² = 0.911). Communication had the strongest effect (β = 0.475, p = 0.000), indicating that improved communication substantially enhances project quality. Reporting also showed a statistically significant positive influence (β = 0.318, p = 0.013), though to a lesser extent. These findings underscore the importance of structured communication systems and regular reporting in ensuring quality road infrastructure. The study concludes that fostering effective collaboration among clients, consultants, and contractors through enhanced communication channels and comprehensive reporting mechanisms is vital for achieving quality assurance. It recommends strengthening stakeholder coordination, institutionalising information-sharing practices, and investing in communication training and digital platforms to support sustainable infrastructure development.