Feasibility study
In this phase the technical and economical proposition of the various possibilities of execution for the tunnel is investigated. Besides bored alternatives also the traditional methods are investigated in this phase.
Preliminary design
In this phase the traditional construction method is detailed further till preliminary design. Advising had also reference to design and fitting in into the landscape of the slip roads.
Final design
In this phase the plan based on cut & cover method is in co-operation with the Engineering-Bureau of the Municipality of The Hague detailed on final design level.