The 4+1 new urban road tunnels in Athens from east to west

Focusing on traffic issues in Athens and the broader metropolitan area, the implementation or planning of new road interventions includes new road tunnels that promise to contribute to a revamped image of the city and aim to improve mobility within it.

From Attiki Odos to Elliniko and even Faliro, underground projects are being prepared or planned, which many consider essential for urban planning. These are set to become new landmarks of the capital, and traffic conditions are expected to worsen significantly if these planned interventions do not take place.

The most advanced of all is the underground Poseidonos Avenue project, which is estimated to be operational by 2026. Additionally, there are plans for the major urban tunnel in Ilioupoli, the tunnel for the extension of Kymis Avenue, the activation of the so-called “ghost tunnels” in Aspropyrgos, and the “pseudo-tunnels” in Faliro.

The undergrounding of Poseidonos Avenue in Elliniko

Another particularly interesting case is the undergrounding of a section of Poseidonos Avenue. It is part of the Phase A development projects for Elliniko and involves an underground section starting from the borders of Alimos and Agios Kosmas, which will rise again at the level of the Elliniko Marina.

The project aims to connect the area of Agios Kosmas with the coastal front, as the creation of the tourist district of Elliniko is planned there. The tunnel will be approximately 1.3 kilometers long and will include three lanes in each direction, maintaining the same number of lanes as currently available. It is a particularly complex project due to its scale and its proximity to the sea.

Currently, the project is at a very advanced stage, with the concrete work on the road tunnel almost completed. According to current estimates, the underground section of Poseidonos Avenue is expected to be operational by 2026.

The Ilioupoli Urban Tunnel

Another new underground project, introducing a completely new axis, is included in the future plans of the Ministry of Infrastructure and Transport for the extension of the Western Peripheral Ymittos as part of the Attiki Odos expansions. This particular project is of great interest as it will ease congestion in the connection between the southern and northern suburbs of the city via Karea Avenue. What does it involve? The extension of Attiki Odos from the area of Katechaki Avenue to Vouliagmenis Avenue through a new “urban tunnel.”

A “urban” tunnel is planned there, with a length of just over 3 kilometers, featuring three lanes in each direction and no exits. It will begin to descend near Kaisariani (where the Western Peripheral Ymittos currently ends) and will connect to Vouliagmenis Avenue near the border of Agios Dimitrios and Ilioupoli, slightly south of the Agios Dimitrios Metro station. The journey through the tunnel will take approximately 1-2 minutes, compared to up to 30 minutes during peak hours today.

Kymis Avenue and the Aspropyrgos Tunnels

At the same time, two more tunnels are planned in the northern and western suburbs of the metropolitan area. The existing Attiki Odos awaits the extension of Kymis Avenue, which is considered the most significant road project in Attica. This project will create a bypass for the “challenging” section of Attiki Odos, easing traffic congestion at the Metamorfosi exit, which currently bears the full load of traffic to and from Kifisos Avenue.

The project includes both open sections and tunnels for its extension. Specifically, it involves an underground tunnel (approximately 1.25 km in length) and a tunnel constructed using the cut-and-cover method (approximately 1.15 km in length). It is worth noting that the relevant tender is currently ongoing but has been blocked due to an appeal filed with the Council of State (ΣτΕ) by the municipality of Herakleio, Attica.

Additionally, there are the tunnels in Aspropyrgos, which were constructed many years ago but have never been put into operation. These tunnels are part of the plan for the Skaramagas Triple Interchange, a project that the Ministry of Infrastructure and Transport is bringing back into focus. The tender is expected to be announced in 2025, and with its completion, the so-called “ghost tunnels” of the area are expected to finally become operational.

The “tunnels” in Faliro

In the Faliro area, two “pseudo-tunnels” have already been constructed. During Phase A of the redevelopment works of the Faliro Bay, a new Poseidonos Avenue was created, but with a significant difference: two above-ground tunnels now dominate the section between the Peace and Friendship Stadium (SEF) and its junction with Syngrou Avenue.

Today, these tunnels might seem purposeless, but in the completed phase of the intervention, a large 240-acre coastal park will be created above them. As part of the project design, to achieve better integration with the Faliro and Kallithea areas, two sections of the highway were chosen to be “covered.”

This led to the construction of these two small tunnels, which will be situated beneath the park once the intervention is complete. Additionally, the plan includes the creation of parking spaces under the park to accommodate visitors, ensuring that the surrounding streets do not become congested.

The second phase of the project will be implemented by the Attica Region over the next three years, as the relevant tender is imminent and will be funded through the 2021-2027 NSRF. This new coastal park will be connected to the Stavros Niarchos Foundation Cultural Center via the Esplanade, creating, together with the Flisvos area, a unified recreational space stretching from the Peace and Friendship Stadium (SEF) to Palaio Faliro.

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