Scientific paper ID 2247 : 2022/3

The construction of infrastructure sites is characterized by:

 long duration - construction production is the stage of the investment process with the longest duration - measured in months, even years,

 high value - up to ten and hundreds of millions of levs,

 high cost of labor and material resources - specialists, workers, materials and machinery,

For these reasons, the regulatory framework is constantly being improved in order to increase the efficiency, safety and legality of the implementation of infrastructure projects.

The decision to build underground transport in Sofia was made in 1968, when Sofia had 600,000 inhabitants. The first technical and economic report on the construction of the metropolis was prepared in 1972. It was put into operation on January 28, 1998. The Republic of Bulgaria has been a member of the European Union since 01.01.2007. Since then, the construction of the subway began to develop rapidly. As of April 24, 2021, the metro in Sofia has a total length of 52 km with 47 metro stations. During the building of metro in Sofia are implemented and applied different national and international forms of legal contracts.

The purpose of the report is to consider and analyze the trends in the implementation of various types of contracts based on good national and international practices in the construction of the metro in Sofia /Bulgaria/.