Construction delays are one of the biggest issues facing the construction industry and affecting delivery in terms of time, budget and the required quality. The characteristics of delay factors and their level of impact vary from project to project, ranging from a few days to years. They have significant financial, environmental and social impacts in construction projects; therefore, it is vital to investigate the causes of delay and analyse their impact. In this context, the research study was initiated to develop a new methodology for analysing and quantifying the impacts of delay factors on construction projects. A comprehensive literature survey was conducted to build up general background knowledge of delay factors in construction projects and particular attention was paid to identifying the potential differences in delay factors between Libya and the UK. A construction industry survey was conducted through a semi-structured questionnaire amongst contractors, consultants and owners. A total of 116 out of 300 responses (38.66%) were received from both countries. Statistical tests including T-test and Wilkinson rank test were executed to analyse the responses and present the findings from the survey. Following the findings from the literature review and an industry survey, a framework of Delay Analysis System (DAS) augmented with simulation model was developed by integrating the importance weight (IW) of each delay factor associated with critical activities using @risk tool. The key function of the system is the flexibility to analyse and quantify the impact in project duration, considering the IW of each delay factor independently. The system was evaluated through two case studies from building projects in Libya using the developed system. The analysis of case study 1 using DAS found that the building project might be delayed by 97 to 103 days when considering the delay factors identified from Libya whereas the project might be delayed by 80 to 85 days when considering the delay factors identified from the UK. The evaluation results from the case study revealed that the impact of delay factors in Libya is higher than in the UK. This confirms that the impact of delay in construction projects is higher in developing countries than in developed ones and varies from project to project in the same country. Finally, it is concluded that the system is a decision-supporting tool that helps to make government departments and decision-makers aware of the significance of delays in construction projects in terms of economic growth and the development processes. The key contribution of this study is the development of a strategy (delay analysis system) for analysing the impact of delay factors in the Libyan construction industry through better investigated, understood and documented reports. The system is expected to help policymakers, decision-makers and others stakeholders within the construction industry to gain a fuller understanding of the industry and to formulate short- and long-term construction strategies and policies that aim to improve the industry’s processes and operations.

Stockholm is one of the fastest growing conurbations in Europe, to accommodate for the increased population and urban growth, the current subway system needs to be extended. Appropriately, a joint initiative regarding housing and infrastructure development was signed in January 2014 by the Swedish government, Stockholm County Council and the afflicted municipalities Stockholm, Solna, Nacka and Järfälla. The joint initiative, the 2013 Stockholm negotiation, presented an extension of the current subway system with a total length of 19,6 km and 11 new stations in Stockholm, Solna, Nacka and Järfälla. Large-scale infrastructure projects often suffer from cost and time overruns. The Stockholm subway construction is no exception and has since the project started collected a delay equivalent of five years for Järfälla and Nacka, and a cost overrun of SEK 9,3 billion. The aim of this thesis is to objectively identify the critical delay factors of the subway tunnel construction in Stockholm and unveil the delay implication on property developers with housing projects in the adjacent areas to the new stations. The thesis will be limited to mainly focus on the extension to Järfälla and Nacka. To investigate the research questions, a systematic integration of quantitative and qualitative data has been collected through literature reviews, 9 interviews with the client, designers, consultants and a survey with 13 property developers. This thesis has identified one critical delay factor, linked to the poor project performance regarding the time overruns. With support from the literature review, interviews and surveys, the observed delay can be described as a consequence of political-economic explanations. The cause for the delay is rooted in the inaccurate estimations and unrealistic expectations presented in the 2013 Stockholm negotiation. Thus, the project delay is to be categorized as non- acceptable, due to a five-year prolonged time plan. Additional delay factors have beenidentified but are not to be viewed as critical. This thesis has also identified a general frustrationamongst the developers in Järfälla and Nacka as they have perceived negative implications as a consequence of the delay of the subway extension. / Stockholm är en av de snabbast växande storstadsregionerna i Europa och för att tillgodose den ökade tillväxten behöver regionen utveckla sin infrastruktur och kollektivtrafik. I januari 2014 undertecknades en överenskommelse, avseende utveckling av bostäder och infrastruktur, mellan regeringen, Stockholm Läns Landsting, Stockholm- och Solna stad, Nacka samt Järfälla kommun. Avtalet benämns som 2013 års Stockholmsförhandling och omfattar en utbyggnad om 11 nya tunnelbanestationer i Stockholm, Solna, Nacka och Järfälla, med en total spårlängd om 19,6 km.  Stora infrastrukturprojekt har historiskt sett blivit försenade och haft budgetöverskridande projektkostnader. Tunnelbaneutbyggnaden mot Järfälla och Nacka har båda blivit försenade med fem år samt överskridit budgeten med totalt 9,3 miljarder kronor. Syftet med denna masteruppsats är att objektivt identifiera de kritiska faktorer som orsakat förseningen av projektet samt redogöra för de konsekvenser som förseningen har orsakat för de bostadsutvecklare med projekt i områdena där de nya stationerna är planerade. Uppsatsen har avgränsats till att enbart skildra utbyggnaden mot Järfälla och Nacka. För att besvara studiens frågeställningar har kvalitativ och kvantitativ data integrerats genom litteraturstudier, intervjuer med 9 nyckelpersoner inom projektet, samt via en enkätundersökning med 13 fastighetsbolag, verksamma i Järfälla och Nacka.  Uppsatsen har identifierat en faktor som ligger till grund för att projektet inte presterat enligt projektets tid- och kostnadsmål. Faktorn har sitt ursprung i de felaktiga och orealistiska beräkningar som presenterades i 2013 års Stockholmsförhandling. Ytterligare förseningsfaktorer har identifierats, men är inte att anses som kritiska eftersom de inte haft en betydande inverkan på projektet och dess färdigställande. Förseningen av projektet är att kategorisera som ej acceptabel med hänsyn till dess uppkomst och omfattning. Mot den bakgrundsdata som samlats in genom litteraturstudier, intervjuer och enkätundersökningar kan förseningen härledas som en konsekvens av politisk-ekonomiska orsakssamband. Uppsatsens resultat visar även på att förseningen orsakat flera negativa konsekvenser för de fastighetsbolag som är verksamma i Järfälla och Nacka, vilket har skapat ett generellt missnöje gentemot projektets beställarorganisation.