<p>In construction projects, each type of delay in implementation and lack of exploitation of them is the precise instance of wasting the resources. The most important resource which is wasted in this regard is the element of time which is the most valuable capital of nations in today&rsquo;s fast-paced world. Sometimes, the profit resulting from early completion of the project may tempt the employers and project owners to reduce the time of project. Some other times, macro policies may urge a project to be exploited earlier than its due date. After introducing the time reduction techniques briefly in this paper, the challenges of these techniques were specified through interviewing with the experts. Then three criteria were selected to investigate the techniques. Using the results of the questionnaire, the impact of these techniques on the criteria was then dealt with in different phases of the project in Design and Build contracts.</p>