CBPM Conference 2026 · Vol. 2026, Issue 1

Understanding Root Causes of Cost and Time Overruns in South African Mega Infrastructure Projects

Lindelani Matshidze, Temitope Omotayo, Abimbola Windapo

Keywords: MegaProjects, Cost overruns, Project Delay, Infrastructure Projects, Infrastructure Delivery

Abstract

This study investigates the root causes of cost overruns and schedule delays in South African mega infrastructure projects. Mega infrastructure projects are defined as large-scale developments valued at approximately US$1 billion or more, characterised by high complexity, multiple stakeholders, and significant socio-economic impact. A qualitative research approach was adopted, using semi-structured interviews with six purposively selecte industry experts possessing extensive experience in the planning, management, and delivery of South African megaprojects. Data were analysed using thematic analysis. The findings reveal that corruption, poor front-end planning, optimism bias, incomplete design and contract documentation, and inadequate project management capacity are the primary causes of cost overruns and project delays. Although these factors have been identified in international studies, the findings suggest that governance weaknesses, institutional constraints, and accountability challenges are particularly influential within the South African construction sector. The study is theoretically grounded in Agency Theory and Optimism Bias Theory, providing insight into how governance failures and unrealistic planning assumptions contribute to project underperformance. The research contributes to the limited body of knowledge on megaproject delivery in developing countries. It offers practical recommendations for policymakers, infrastructure clients, consultants, and project managers to improve project performance and infrastructure delivery outcomes in South Africa.