Metro and light rail sides of operation vary and might not match railways or roads in their country. Some systems where the metro matches the side of the national rail network but not the roads include those in   Bilbao, Buenos Aires, Cairo, Catania, Jakarta, Lisbon, Lyon, Naples, and Rome. A small number of cities, including Madrid and Stockholm, originally ran on the same side as road traffic when the systems opened in 1919 and 1950 respectively, but had road traffic change in 1924 and 1967 respectively. Conversely, metros in France (except for the aforementioned Lyon) and mainland China run on the right just like roads, while mainline trains run on the left.
A small number of systems have situational reasons to differ from the norm. On the MTR in Hong Kong, the section originally known as the Ma On Shan line (now part of the Tuen Ma line) runs on the right to make interchanging with the East Rail line easier, while the rest of the system runs on the left. On the Seoul Metropolitan Subway, lines that integrate with Korail (except Line 3, which is disconnected from the rest of the network) run on the left, while the lines that are not run on the right. In Nizhny Novgorod, Line 2 runs on the left due to the track layout when it first opened as a branch of Line 1. In Lima, Line 1 runs entirely on the left, while Line 2 runs entirely on the right.
Metro Line M1 in Budapest is the only metro line to have switched sides. It originally ran on the left but switched to right hand-running during the line's reconstruction around 1973.
Because trams frequently operate on roads, they generally operate on the same side as other road traffic.