Cost-effectiveness analysis of a road improvement proposal based on sustainability Indicators: Case study Al-Nebai-Baghdad highway

Abstract

Involving the sustainability assessment in the phases of road development project has become necessary to avoid unforeseen consequences. In Iraq, there is a noticeable lack of the environmental and social assessment of the development project. The economic assessment also needs to consider the project life cycle. The unavailability of validated and comprehensive methodologies of assessment is the main obstacle. Therefore, this study aims to outline a methodology of environmental, social and economic (ESE) assessment during pre-construction stages. The rehabilitation and upgrading project of Al-Nebai-Baghdad Highway is selected for this study. The ESE indicators are selected based on the available data and techniques. The needed data; traffic volume, pavement condition, and geometric design characteristics; are collected to process the engineering and the ESE assessment through aggregating several methodologies and analyse the results using thr cost-effectiveness technique. The results of the engineering assessment showed upgrading the traffic level of service to D due to adding a lane when the pavement condition was upgraded to good condition due to a new overlay. The results of the environmental assessment in terms of vehicle emission stated that the new pavement reduced the emission by1831967 tons but the emission due to widening increased by 1046100 tons. The social assessment indicated that the road casualties reduced by 38.5% but it boosted over the service life. The economical assessment demonstrated the worthiness of the project; the Net Present Value is 76,153,580$, the B/C is 3.45 and the IRR is 35.04. It can be concluded that the ESE assessment is applicable and effective in figuring out the negative and positive consequences over the service life. However, improving the data collection system can enhance the comprehensiveness of the adopted methodologies and consider more indicators.