quality:correction, structural:summarization, stylistic:tone, structural:expansion
Transport

Sweden has 162,707 km (101,101 mi) of paved road and 1,428 km (887 mi) of expressways. Motorways run through Sweden and over the Øresund Bridge to Denmark. Sweden had left-hand traffic (vänstertrafik in Swedish) from approximately 1736, but after the Riksdag passed legislation in 1963 changeover took place on 3 September 1967, known in Swedish as Dagen H.

The Stockholm metro is the only underground system in Sweden and serves the city of Stockholm via 100 stations. The rail transport market is privatised, but while there are many privately owned enterprises, the largest operators are still owned by the state. Operators include SJ, Veolia Transport, Green Cargo, Tågkompaniet and Inlandsbanan. Most of the railways are owned and operated by Trafikverket.

Most tram networks were closed in 1967. But they survived in Norrköping, Stockholm and Gothenburg, with Gothenburg tram network being the largest. A new tram line opened in Lund on 13 December 2020.

The largest airports include Stockholm–Arlanda Airport (16.1 million passengers in 2009) 40 km (25 mi) north of Stockholm, Göteborg Landvetter Airport (4.3 million passengers in 2008), and Stockholm–Skavsta Airport (2.0 million passengers). Sweden hosts the two largest port companies in Scandinavia, Port of Göteborg AB (Gothenburg) and the transnational company Copenhagen Malmö Port AB. The most used airport for a large part of Southern Sweden is Kastrup or Copenhagen Airport which is located only 12 minutes by train from the closest Swedish railway station, Hyllie.

Sweden also has a number of car ferry connections to several neighbouring countries. This includes a route from Umeå across the Gulf of Bothnia to Vaasa in Finland. There are several connections from the Stockholm area across the Sea of Åland to Mariehamn in Åland as well as Turku and Helsinki on the Finnish mainland and beyond to Estonia and St Petersburg in Russia. Ferry routes from the Stockholm area also connect with Latvia and Poland across the Baltic Sea. The ferry ports of Karlskrona and Karlshamn in southeastern Sweden serve Poland and Lithuania. Ystad and Trelleborg near the southern tip of Sweden have ferry links with the Danish island of Bornholm and the German ports of Sassnitz, Rostock and Travemünde, respectively, and ferries run to Świnoujście, Poland, from both of them. Trelleborg is the busiest ferry port in Sweden in terms of weight transported by lorry. Despite the opening of the fixed link to Denmark, the Øresund Bridge, the busiest ferry route remains the short link across the narrowest section of the Øresund between Helsingborg and the Danish port of Helsingør, known as the HH Ferry route. There are over seventy departures a day each way; during peak times, a ferry departs every fifteen minutes. Ports higher up the Swedish west coast include Varberg, with a ferry connection across the Kattegat to Grenaa in Denmark, and Göteborg, serving Frederikshavn at the northern tip of Denmark and Kiel in Germany. Finally, there are ferries from Strömstad near the Norwegian border to destinations around the Oslofjord in Norway.

Sweden has two domestic ferry lines with large vessels, both connecting Gotland with the mainland. The lines leave from Visby harbour on the island, and the ferries sail to either Oskarshamn or Nynäshamn. A smaller car ferry connects the island of Ven in Øresund with Landskrona.