Line D will connect the historic city to the north, with the Talenti, Montesacro and Salario districts and, to the south, with Trastevere, San Paolo, Marconi, Magliana and EUR.
The basic route originates from Piazzale dell’Agricoltura, in the core of EUR. After connecting with line B and the Rome-Lido railway, line D crosses the Tiber River and heads north to cross the Magliana Nuova district, and continues along the Viale Marconi line up to Trastevere station, where it exchanges with regional rail services and with the one to the airport. After crossing the Trastevere district, proceeding north, the line once again passes under the river at the Tiber island, then continues north-east, to exchange with line C and, subsequently, with line A after having served the central area with a new station near Piazza San Silvestro. After passing the Aurelian Walls, the line crosses the Trieste-Salario district and the Aniene one, to then continue eastwards on via dei Prati Fiscali and viale Jonio, thus ending in the Talenti district. The main role of line D is to complete the coverage by mass public transport of those urban areas not served by the subway lines A, B and C and characterized by a density of residents and workplaces compatible with this mode of transport.