SELAMAWIT KIFTAGA NAMAGA2026-02-172018-10-11https://etd.hu.edu.et/handle/123456789/845Completion of a project is considered as the most important factor of successes of road projects which helps to decrease problems for all concerned parties and give new chances to a county's economy. Delays in completion of road projects will result in significant loss of benefits for all road users. Accordingly, this research is carried out with the view of evaluating the impacts of road construction delays on transport costs and benefit considering Hageremariam-Yabelo Road. Questionnaire surveys were used to collect data on causes of delays and impact of delay on vehicle operating cost as well as an analysis was conducted by using the Likert Scale with mean score value. A total of 35 responded questionnaires from the client, consultants and contractors were collected. In addition, pertinent data were collected from vehicle operators on Hageremariam Yabelo Road project. Respondents identified twenty-seven (27) causes of delays and nine (9) impacts. The most important causes of delays were: delays to furnish and deliver the site (right of-way problem) and lack of possession of the site in various locations; variation of order (additional works not considered during the first time); and late site mobilization. The most common impacts of delays regarding vehicle operating cost were identified as; working hours per year (frequency of journey per day); tire consumption / tier-wear and average vehicle service life. This research also used the Highway Development and Management (HDM-4) tool in quantifying additional costs due to delays in respect of road agency and road user costs with the total loss of benefits. Using the Model, results were generated in the case of both alternatives (with delay and without delay) of the subject construction project. Overall, the 'with delay' alternative was compared with the 'without delay' alternative and the total transport costs increased by Birr 674.22 million. The amount of lost benefits from vehicle operating cost savings, travel time cost savings and accident cost reduction that resulted in the case of 'with delay' alternative was calculated at Birr 17.49 million. It is believed that these findings will guide to improve the performance of the construction industry of Ethiopia in the futureenroad construction delaycauses of delayimpacts of delaysHDM-4time and cost overrunsbenefitsThesis