Transportation industry is basically a service sector component. It is of great importance to traffic engineers and planners to understand and evaluate the quality of service provided by transport facilities. Highway Capacity Manual (HCM), with all its revisions since 1950, is the pioneer document in this area. It quantifies the concept of capacity for a transport facility and lays the foundations for estimating the level of service (LOS) being provided by that facility to its users. This thesis is an engineering project management study. It is about evaluation and improving multi-lane highways in Iraq. The research study was conducted on one main multi-lane highway in Baghdad, including: Al- Dora intersection to Al- Rashid interchanges, where this highway is considered as a major highway with high volume traffic in Iraq. Highway Capacity Software (HCS 2010) program software was used to evaluate and improve the level of service and traffic conditions for the highway for existing conditions (year of the study-2018), short-term conditions (2023) and mid-term conditions (2028). Evaluation shows that all segments are operating at LOS E or LOS F for existing conditions, short-term conditions and mid-term conditions. The segments that operated at LOS E or LOS F for existing, short-term and mid-term conditions improvements are suggested by modifying the geometric and traffic conditions and changing the highway to a freeway facility; in order to operate at better LOS. Management flow diagrams were prepared for decision makers to be a guide for future planning programs. Keywords: Highway Capacity, Highway capacity manual (HCM 2010), Multi-lane Highway, Expressway (Basic freeway facilities) in Iraq, Level of Service (LOS), Highway Capacity Software (HCS, 2010).