The eastern portal of the tunnel is located at coastal cliff area between Žusterna and Izola. The cliff is made of flysch in a typical orange-yellow colour and is heavily covered in plants. The architectural solution to the portal caused minimum changes in the existing wall.
The tunnel portal is of reinforced concrete, its slab preserves the shape of a contour line of the flysch layer which follows the configuration of the ground and assumes the typical form and texture of the environment The slab or rather the roof of the portal physically protects the road against possible crumbly materials and defines the visible limit of the intervention. The area of the portals below the slab is designed with support walls coated with locally obtained sandstone of dimensions 30x30x100 poured into mortar with deep seams. This is why the stone gives an impression of being split/cut.
As the western portal is located in the green, rural area of the Pivol valley, the main guidance in design was to reduce intervention into the environment and to preserve as many green surfaces as possible.
