The B-10, also known as Ronda Litoral, is a freeway in Catalonia, Spain partially encircling Barcelona passing through the eastern side of the city. It starts at Nus de la Trinitat interchange in northern Barcelona and runs along the entire length of the Besòs River and the city's coastline south to Nus del Llobregat interchange in Barcelona's southern suburbs, where it becomes the Autovía A-2. Both north and south end interchanges link the freeway to the B-20 or Ronda de Dalt, which encircles Barcelona passing through the western side, jointly forming a beltway commonly referred to as the rondes that surrounds the city. The freeway features a mix of below-grade, at-grade and covered tunnel sections, mainly as it passes through central Barcelona, where it is only two lanes in each direction while the other sections are three lanes. It becomes a segregated urban highway as it passes through central and northern Barcelona so that all its signposting becomes green and is maintained by local authorities. In contrast, the southern section of B-10 is considered to be part of European route E90 and is signposted in blue following the formal colour scheme for motorways since it serves as a continuation of the Autovía A-2. In addition, unlike the rest of the route, this section is named Cinturó Litoral and is maintained by the Spanish Government. Although the speed limit is 80 km/h along the urban freeway section and 100 km/h along the interurban section, car's average top speed is lower due to traffic congestion as it serves as an arterial corridor to access Barcelona by road, and even average topspeed may reach 20 km/h during rush hour. Additional restrictions for heavy goods vehicles are applied on the section situated between Montjuïc–Morrot and Rambla de Prim near Sant Adrià de Besòs, whereby weight limits is posted 12 tonnes and all vehicles over 12 meters long are banned from that section.
Exit list
Exits on the rondes are numbered 1 to 30 anticlockwise from Nus de la Trinitat according to the beltway that Ronda Litoral and Ronda de Dalt freeways form around Barcelona so that exits on Ronda de Dalt are officially numbered 1 to 16, while on Ronda Litoral are numbered 17 to 30. Strangely enough, while the entire urban highway section follows the exit numberingscheme of the rondes, the interurban section that is maintained by the Spanish Government does not and exits on this section are numbered 13 to 19 following its own scheme. In addition, route markers are placed north–south in relation to Nus de la Trinitat, where the road's "Kilometre Zero" is placed, on the contrary of the exits' numbering.
