Abstract:
Delays in construction of infrastructure projects not affect owners, but also cause inconvenient to road users. Generally in public projects, contractors would be penalized for delay at the fixed rate according to the regulation of the office of the Prime Minister which has been used since 1955. Therefore, this penalty rate may not reflect the real loss of project delay. This study demonstrates such loss including loss to owners and impact to road users due to construction delay of eight case studies from three organizations: Metropolitan Waterworks Authority (MWA), Metropolitan Electricity Authority (MEA), and Bangkok Metropolitan Authority (BMA). The result could could be used as a basis for determining appropriate penalty charges for construction delay. Evaluation of losses is different among each organization depending on the related parameters. This study uses a similar approach for MEA and MWA in determining the loss of net income from selling utilities due to the service disruption and the cost of interest. For BMA, which has no income in providing service, the loss due to construction delay is determined from the cost of interest and a loss in benefit for not having such service. Moreover, these kinds of infrastructure projects usually cause impact to road users. Therefore, this study also determines the increase of road user costs which are calculated based on vehicle operating costs and driver delay costs due to vehicle speed reduction during construction. Factors influencing change in speed are traffic volume, number of traffic lanes, lane width, median type, and lateral clearance. Losses calculated from the presented model ranges between 0.018% to 0.441% of project construction cost. The calculated losses from the model are higher and lower than the actual penalty rate in three and five projects respectively. Five projects caused low impact because the construction was only allowed at hight, and the calculation does not include all impacts. Most calculated losses are from the increase of road user costs and the loss in benefit of the public for not having the service. The result from this study can be used as a guideline for determining the real loss due to delay in construction. Consequently, it can be used to develop appropriate penalty charges for delay to reflect the actual losses.