Safety and protection of health on construction sites and protection of third parties during construction is a complex problem. It is affected by contractor’s policy on ensuring thorough abidance to security requirements but, in the first place it is affected by submitters and their irresponsible appreach to protection of life and health of the construction workers. They believe that ensuring safe work enviroment would reset in increased cosi of the construction. This doctoral thesis answers the question how to guarantee safety on construction sites. The main purpose is to show that early detection of risks does not increase the construction costs but ensures safety of workers protection of third parties. Finally, the doctoral thesis provils methodology, which guides the contractor in how to proceed in order to meet the budget, schedule and safety requirements. In regard of the variety of different construction sites and works this docáral thesis focuses explicitly on line constructions.