The project team fabricated the bridges in segments off site, eliminating years of work in the roadway. The segments MassDOT used are called PBUs or Prefabricated Bridge Units. Each PBU is composed of a concrete deck with two steel beams underneath it. The PBUs were installed by crane and connected with a rapid-setting concrete, replacing at least one bridge each weekend. By replacing the bridges with bridge units that were fabricated off-site, MassDOT eliminated years of work in the roadway.