Economic and Environmental Assessments for Constructing New Roads: Case Study of Al-Muthanna Highway in Baghdad City

The geographical area of this study located between the Army canal and Al-Sadr City is characterized by high-density population and lack of high-speed highways. This area is facing a low service level during traffic congestion resulting from an inefficient and poor road network. A traffic study has been done which recommended the construction of a new road parallel to the existing one, but with higher standards. This research aimed to evaluate, economically and environmentally, the feasibility of constructing a road for Al-Muthanna highway. This research is based on the hypothesis that the present road exhibits a relatively severe condition whereas the suggested road will be an asphalt pavement with a high-quality status. The traffic volume data was collected using a manual counting method for seven days from 7:00 am to 4:00 pm to quantify the average daily traffic and peak hour volume. In addition, the number of lanes required for LOS (C) was determined. The construction and maintenance costs for the road were also calculated. Reduction in road user costs for both the present and proposed roads were estimated as advantages. The economic study is done by balancing the reduced total road costs and their advantages to the basic year. The assumed discount rate in this study was 8%. To discover the economic viability, various standards were verified. These standards are Benefit–Cost Ratio (B/C), Net Present Value (NPV), and Internal Rate of Return (IRR). The outcomes revealed that NPV exhibited an encouraging value, that indicated that total benefits were larger than costs. Moreover, the B/C ratio was found to be more than 1.0, which was promising. Lastly, the IRR was found to be greater than 8% as suggested in the road projects.