Its length and the surface surrounded by the M-30 is comparable to the Boulevard Périphérique of Paris, the Grande Raccordo Anulare of Rome or the London Inner Ring Road.

The M30 is the busiest Spanish road, famous for its traffic jams, and surrounded by several landmarks such as Torrespaña (one of the tallest structures in Madrid), the national headquarters of IBM, and passed under the Vicente Calderón Stadium.

From 2005 to 2008, major upgrading works took place, and now a significant portion of the southern part runs underground.

[3] The M-30 surrounds the inner core (the central districts) of Madrid: Centro, Arganzuela, Retiro, Salamanca, Chamartín, Tetuán, and Chamberí, as well as a small part of Moncloa-Aravaca.

This core is home to one quarter of the population of Madrid (about 800,000 people) and is, in average, wealthier than the rest of the city.