Abstract
Road construction projects in Kenya continue to experience persistent cost overruns, schedule delays, and inefficient resource utilization, despite substantial public investment in transport infrastructure. In Mombasa County, unique environmental and logistical conditions, including saline soils, port congestion, and high urban density, further complicate project delivery and increase the risk of cost escalation. Although project cost management has received increasing scholarly attention, limited empirical evidence exists on the influence of cost estimation and cost planning on the performance of road construction projects in this context. This study examined the influence of cost estimation and cost planning practices on the performance of road construction projects in Mombasa County, Kenya. The study was anchored on Resource Dependency Theory and the Theory of Constraints and adopted a descriptive survey research design. The unit of analysis comprised 18 road construction projects implemented between 2020 and 2024, while the unit of observation consisted of 180 project staff. Data were collected using semi-structured questionnaires containing both Likert-scale and open-ended questions. Instrument validity and reliability were established through a pilot study involving 18 respondents. Quantitative data were analysed using descriptive statistics, Pearson's correlation, and multiple regression analysis, while qualitative responses were analysed using thematic content analysis. The findings revealed that cost estimation had a strong positive and statistically significant relationship with project performance (r = 0.816, p < 0.001), while cost planning also exhibited a positive and significant relationship with project performance (r = 0.527, p < 0.001). The study concludes that strengthening cost estimation and cost planning practices significantly enhances the performance of road construction projects. It recommends improving the accuracy of project cost estimates through comprehensive cost analysis and realistic forecasting, while strengthening cost planning through effective cost baseline development, cash flow planning, and cost forecasting to improve project delivery.
Keywords: Cost estimation, cost planning, project cost management, project performance, road construction projects, Mombasa County, Kenya.