In public transport

Public transport

Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...

, a short turn or turn-back is an earlier terminus on a bus or rail line that is used on some scheduled trips that do not operate along the full length of the route.

Short turns are practical in scheduling when the short-turning bus can proceed through its layover

Layover

In transportation, a layover, also known as lays over or stopover, is some form of a break between parts of a single trip.-In mass transit:...

 at the short turn loop, then start a run in the opposite direction, all while reducing the number of buses needed to operate all trips along the route as opposed to if all scheduled trips operated to the terminus of full-length trips.

Short turns require the availability of a separate loop on the bus or rail line where the vehicle can turn around and lay over. On bus routes, this could be streets that can accommodate bus traffic. On a rail line, this means a location where the layover does not interfere with other rail traffic.

On rail lines, short turns are more limited due to the number of crossovers between tracks.

Demand for services

Short turns are used on bus routes and rail lines where there is a lower demand for service along the part of the route not served by the short-turning trips. This helps in reducing operating costs. While more economical, these short turns do not necessarily reduce the number of buses needed to operate the full amount of service along the route.

Crowd management

Short turns can aid in reducing overcrowding of buses. By scheduling uneven intervals between full-length and short turn trips, this may lead to accommodation of more riders on the trips coming out of the short turn layover location.

Short turns can be used to reduce bus bunching

Bus bunching

In public transport bus bunching, clumping, or platooning refers to a group of two or more transit vehicles along the same route, such as buses or trains, which are scheduled to be evenly spaced, running in the same location at the same time...

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Branches

Some bus and rail routes have multiple branches serving different locations, but are otherwise identified with the same designation. These separate branches are not officially short turns, but in such an operation, the common part of the route has more service than the individual branches, just like a short turn service.

Some multi-branch routes have a close to even number of trips along each branch. Others have a main branch where the majority of service operates, along with selected to other locations. These selected trips sometimes operates only during certain hours of the day, during peak hours, on certain days of the week, or to meet the needs of a particular employer.

An example of a multi-branch service is the MBTA Green Line

Green Line (MBTA)

The Green Line is a streetcar system run by the Massachusetts Bay Transportation Authority in the Boston, Massachusetts area of the United States. It is the oldest line of Boston's subway, which is known locally as the 'T'. The Green Line runs underground downtown and on the surface in outlying...

, which operates four branches. The branches fan out on the surface west of the downtown region, but operate through a subway tunnel in downtown. Approximately three-quarters of eastbound trains also short-turn in the downtown tunnel - two-thirds of those at Park Street and one-third at Government Center

Government Center (MBTA station)

Government Center is an MBTA subway station and a transfer point between the Green Line and the Blue Line. It is located at the intersection of Tremont, Court and Cambridge Streets in the Government Center area of Boston.-History:...

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