Buses in Helsinki
Local and regional bus services are a large part of public transport in the Helsinki region. HSL bus services include internal services in Helsinki, Espoo, Kauniainen, Vantaa, Kerava, Kirkkonummi, Sipoo, Siuntio and Tuusula and regional services between them. Since 2010, the planning and timetabling of these bus routes have been done by Helsinki Region Transport, an organisation to which the aforementioned municipalities belong. Prior to HSL's inception, Helsinki's internal lines were the responsibility of Helsinki City Transport, with all other bus services being organised by YTV, HSL's predecessor. Principles of line numbering Bus lines running solely inside the municipality of Helsinki have two-digit numbers, except for lines 52 and 53, which extend into Espoo, as well as trunk line 30 and night line 95N, both of which extend into Vantaa. Three-digit numbers are used by all other lines, (except for Helsinki internal lines 500, 506, 611B and 831(K), as well as part of Helsinki's minibus routes). Some lines have a letter or two at the end of their number, for example 611B. This denotes that the line differs from the main route in some way. For example, the route of line 611B is shorter than that of line 611. These letters mean the following: A = a lengthened route B = a shortened route (denotes an evening route for lines 82B) H = a tram route ending at Töölö, Koskela or Vallila depot K = a lengthier route through a smaller neighbourhood or termination somewhere different M = a metro replacement bus terminating at Mellunmäki. N = night line R = a line operated by a robot bus (all lines have been discontinued) T = a lengthier route, often involving serving long cul-de-sacs or (occasionally) termination somewhere different (in the case of buses to southern Espoo this denoted going via Lauttasaari) V = a quicker route, usually going along more main roads, or via an industrial area, usually only during peak hours OR a metro replacement bus terminating at Vuosaari. X = a metro, train or tram replacement bus Z = a quicker route, usually along more main roads or highways, again usually only during peak hours. Operation hours The majority of lines run between 5:00 and 23:30, with more popular lines continuing until 1:30. Only a small amount of lines run between 1:30–5:00 on weekdays, mainly trunk lines and lines to/from Helsinki Airport. Night lines run mainly on weekend nights between 1:00 and 4:00. This is the only time that most areas have a direct bus connection to central Helsinki, as most daytime bus lines are feeder lines to a train or metro station. Night lines in east and northeast Helsinki and southern Espoo are an exceptional case in the HSL area, as most lines in these areas tend to start operation between 23:00 and 00:30. Individual lines in other areas may also start at this time. The main reason for this is that the metro stops running at around 23:30, rendering feeder lines in east Helsinki and southern