Plan for two-storeyed urban tunnel and new flyovers in Athens’ Southern Suburbs with 170 mn euros

An undoubtedly advanced proposal was presented in the recent soiree organized by the Technical Chamber of Greece, in the framework of “value engineering” and with regard to the construction of an urban tunnel in Ilioupoli area and the introduction of flyovers for a section of Vouliagmeni Ave.

This double proposal has an overall cost of 170mn euros, separated in 130mn for the tunnel and 40mn euros for the intervention in Vouliagmeni Ave. Pioneering elements of this proposal are the construction of a two-storeyed tunnel, which will be incorporated in the dense urban grid more easily, the widening of Vouliagmeni Ave. to 4 lanes per direction and flyovers’ construction up to Alimou Ave.

The proposal

According to the presentation, the project could start from the height of Kesariani flyover (Attica Motorway) until the beginning of the planned Ilioupoli Tunnel, with a length of approximately 2.5 km, where the existing road would be converted to a covered motorway, featuring 3 lanes per direction and 3 additional flyovers ending at Vouliagmeni Ave.

Traffic on a daily basis is estimated at 40,000 vehicles for the two-storeyed tunnel, serving 2 directions on 2 different levels, intended for passenger cars only and a speed limit of 70 km/h. The inclination of the tunnel across its length will not exceed 4,30%. The first kilometer will be opened with the use of New Austrian Tunneling Method (ΝΑΤΜ) and Open Face Shield (OFS) whereas the remaining 2,100 meters will be opened with Cover & Cut.

For the modification of Vouliagmeni Ave. and the introduction of a 4^th lane, the removal of the existing central reservation and the construction of a concrete parapet in the middle is under consideration.  The “new” Vouliagmeni Ave. could feature up to 4 flyovers according to the plans presented. Other innovative elements are the minimization of expropriations’ costs and the utilization of new technologies.

Funding model

According to the proposal, a loan could be issued based on the income deriving from the tolls of Attica Motorway. After 2024, when the concession ends, the next steps are outlined as such: the establishment of a Projects’ Management Company, with the sole shareholder being the Greek State and thereafter the establishment of a Special Purpose Company that will undertake the maintenance of Attica Motorway, among others.

Questions

This very interesting proposal is, nevertheless, subject to clarifications as there are still unexplained issues regarding its implementation and development:

– Is the additional traffic load, that will be created from Hellinikon, also estimated in the current proposal?

– There is no apparent provision for the modification of Vouliagmeni Ave. at least up to Hellinikon.

– To what extent, existing routes will be burdened due to heavy vehicles’ exclusion from the planned infrastructure?

– In what way, the exclusion of touristic and urban buses from the urban tunnel will be managed?

– The upgrade of Vouliagmeni Ave. could be accompanied by the development of a cycle path and adequate space for pedestrian traffic.

Nikos Karagiannis-ypodomes.com

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