Archive:Hong Kong Mass Transport Study/Glossary of Technical Terms

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Appendix E

Hong Kong Mass Transport Study Glossary of Technical Terms

GLOSSARY OF TECHNICAL TERMS

ACCESSIBILITY RATING

A numerical rating for each zone that is a function of employment and the total time to travel to all other zones.

ATTRACTION

The non-home end of a home-based trip; the destination of a non-home-based trip; the "purpose" end of a trip. (See also "Generation".)

BALLAST

Crushed stone upon which the "sleepers" rest.

BASE YEAR

1965; most of the surveys upon which the study was based were conducted in the summer of 1965.

BOGIE

Under-carriage with two or more wheel-pairs, pivoted below the end of a locomotive or railway car.

BOREHOLE LOG

A borehole is a hole driven into the ground to obtain information about the underlying strata. A borehole log is a record of the sinking of the borehole, listing types of material encountered at various depths.

CANT

Cross slope of track on curves.

CAR OCCUPANCY

The average number of persons in a car, including the driver.

CAR-OWNING HOUSEHOLD

A household in which at least one member has available for regular personal use a car in operating condition, whether owned outright, subject to hire purchase, borrowed, assigned by a company or public authority, or other. Households contacted during the course of the survey were classified as car-owning if they so qualified on the day of the interview.

CATEGORY ANALYSIS

A statistical technique of placing each household into one of a large number of categories according to its characteristics and expressing from the trip making information of the sampled households in each category, an average trip generation rate for various modes and purposes.

CENTROID

A point which represents a traffic zone for traffic analysis purposes.

CORDON

An imaginary line which completely encloses a given area and at which traffic counts and interviews may be taken for control purposes.

CORRIDOR, TRAFFIC CORRIDOR

A group of related roads serving similarly oriented traffic movements.

DESIGN YEAR

The design year is considered to be 1986 but may be sooner or later if future growth is different than was projected.

DESIRE LINE

A line drawn between the origin and the destination of a traffic movement irrespective of the routes traversed, of width proportional to the volume of that movement.

DWELLING

A building or part of a building which provides living quarters. In some cases a single dwelling contains more than one household.

EMPLOYEE

Any working household member, gainfully employed for wages or salary in return for working 10 or more hours per week at the time of interview, including self-employed persons.

GENERATION

The home end of a home-based trip; the origin of a non-home-based trip. (See also "Attraction".)

GOVERNMENT-AIDED HOUSING

This is taken to mean those estates wholly controlled by the Housing Authority, the Housing Society plus the Government Low Cost Housing estates built by the Public Works Department but managed by the Housing Authority.

HEADWAY

The time spacing between successive vehicles moving past a point in a given direction.

HOME-INTERVIEW SURVEY

A survey conducted in a selected sample of homes to obtain information about household and person characteristics and about all travel on one day for each member of the household.

HOUSEHOLD

A person living alone or a group of persons living together, partaking of meals together and benefiting from common housekeeping.

INCOME

Total gross income before tax or other deduction, of all members of a single household received from all sources, including wages or salary for employment, profits and salary from business, and pensions.

INTER-ZONAL TRIP

A one-way movement between two zones.

INTRA-ZONAL TRIP

A one-way movement within a zone.

LAND USE

A town planning term describing the type of use to which any given portion of land is put. Land uses were classified into eight categories in the various origin and destination surveys.

LINK

An element in a network which connects two nodes.

LINKED TRIP

A trip using more than one form of powered conveyance and therefore comprising two or more unlinked trips.

MINIMUM PATH

The route of travel between a pair of traffic zones which has the least accumulation of time, distance or other link parameter.

MODAL DISTRIBUTION, MODAL SPLIT

The proportions of trips using various modes of travel.

MODE OF TRAVEL

A form of tranpsort used for a person trip. The term generally refers to one of the following motorised modes: automobile, motor cycle, pak pai, taxi, public car, bus, tram, railway, ferry, rapid transit or goods vehicle. Trips on foot and by pedal cycle are generally excluded from studies of modal distribution.

NETWORK

A diagrammatic representation of a road, bus, rail or other transportation system. A network consists of a number of links.

NETWORK CODING

The process consisting of the preparation of network link tables from which link data cards are punched. The principal link data recorded are the numbers of the pairs of nodes which define each link, the length, and the average travel time.

NEW TERRITORIES

For the purposes of this study the New Territories consists of the area covered by the New Territories Administration. All of the Colony except the "Urban Area".

NEW TOWNS

Planned communities in the New Territories. There will be three new towns; Tsuen Wan which is already under construction, Sha Tin and Castle Peak.

NODE

A numbered point which defines the end of a link in a network.

NON-CAR-OWNING HOUSEHOLD

A household, no member of which has regular use of a car, as defined under "car-owning household".

OTHER HOUSING

This house type includes all forms of private residential accommodation ranging from a bed-space or cubicle in a room or cockloft to a single family detached dwelling. It also includes all Government, Military, Police and Fire department quarters; housing provided by co-operative building societies and by voluntary organisations. Company Housing of all types is also included under this heading.

PAK PAI

Literally "white plate"; a private car used illegally as a taxi.

PARAMETER

A variable used in statistical analysis to indicate (quantitatively) a characteristic of the population or item being studied.

PEAK HOUR

The hour of maximum traffic flow each day.

PRIMARY ZONE

Combination of subzones identified by the first digit in three digit subzone numbers. The PTSU established 10 primary zones in the Colony. (See "subzone".)

PROGRAMME

A sequence of coded instructions, usually stored on magnetic tape, used to solve a problem by electronic computer.

PURPOSE

See "Trip purpose".

RAPID TRANSIT

Grade-separated rail system with high acceleration and fast loading characteristics. Generally with stops or stations one-half mile or more apart.

REGRESSION ANALYSIS

A statistical technique for determining mathematically the relationships between two or more variables.

RESETTLEMENT HOUSING

This means the multi-storey housing designed and built by the Public Works Department originally to rehouse squatters but now extended in scope to house tenants of buildings adjudged to be dangerous, compassionate cases and victims of natural disaster, people from cottage resettlement or resite areas, squatters on Crown Land, tenants of overcrowded resettlement rooms and pavement squatters. At base year, inhabitants of areas designated by the resettlement department as cottage resettlement areas are included under this heading; they will all be rehoused by 1986.

SCREEN LINE

An imaginary line, generally following a natural barrier, along which traffic counts or interviews may be taken for control purposes.

SECONDARY ZONE

Combination of subzones identified by the second digit in three digit subzone numbers. The PTSU established 51 secondary zones in the Colony. (See "subzone".)

SECTOR

A geographic area used for the presentation of planning and trip data that may be all or part of a primary zone. The urban area has been divided into 20 sectors.

SERIAL CONTRACTING

In serial contracting, the first project of a series is placed with a contractor after competition; this stage of the contract is specified in detail, and bills of quantities are available. Subsequent projects are then undertaken by the same contractor based on prices for items in the first project, and rates for new items in the subsequent projects are negotiated.

SHIELD (TUNNEL)

A steel hood used to protect men driving a circular tunnel through soft ground. It is driven forward by jacks around its edge which push on the previously completed tunnel lining. Many modern types of shield are equipped with mechanical excavating and loading machinery.

SLEEPERS

The cross supports to which rails are attached.

SQUATTER HOUSING

This definition is used at base year only and covers those people living in illegal structures on Crown Land, including a shack or lean-to on a pavement or street, structures in resite areas, caves, tunnels or shacks erected on roof tops. Not included in these definitions are those places of residence such as non-domestic space in garages, under staircases, in corridors nor those in workshops, shops or factories.

STATION

An off-street loading facility for a public transport vehicle. A rapid-transit station includes the platforms giving access to the rapid-transit vehicle, the ticket halls, the associated pedestrian ways and escalators.

STUDY AREA

The entire Colony of Hong Kong.

SUBZONE

Small geographic area identified with a three digit number. The PTSU established 139 zones in the Colony for the base year. Some slight adjustments resulted in 145 zones in the design year. (See "Traffic Zone".)

SURFACE TRANSPORT

Non-grade separated mass transport.

SURVEY AREA

The area in which the basic origin and destination surveys were conducted; Hong Kong Island, Kowloon and New Kowloon.

SYSTEM

When used alone, comprises the combination of all modes of public transport and their routes. When used in conjunction with a type of vehicle, it comprises all of the routes operated by that type of vehicle, that is, bus system, tram system, rapid-transit system, etc.

TERMINAL, TERMINUS

Station at the end of a transportation facility. Such a station would be specifically constructed to cater for the transfer and distribution of passengers, it would also cater for the storage, and turnaround of the transportation vehicles and in some cases for maintenance of vehicles and the handling of goods traffic and materials.

TRAFFIC ASSIGNMENT, ASSIGNMENT

The process whereby trips determined from an origin and destination survey are assigned (allocated) to definite routes (existing or planned), based on factors known to influence route selection, the primary factor being travel time.

TRAFFIC DESIRE

A movement between one area and another irrespective of the routes traversed. (See "desire line".)

TRAFFIC MODEL

A series of mathematical formulae expressing the actions and interactions of travel and land use and other planning factors in such a manner that travel patterns can be synthesised or estimated from given assumptions about these factors.

TRAFFIC SYNTHESIS, SYNTHESIS

The process of traffic estimation by the application of mathematical formulae (a traffic model) which simulate the travel behaviour of persons and vehicles by categories of trip purpose, mode, etc.

TRAFFIC ZONE, ZONE

The basic unit of area for traffic analysis, delineated with regard to the main road system, major barriers to traffic flow, land-use characteristics and other traffic engineering considerations. (See "subzone".)

TRAVEL TIME

The average total running time between one node and another including delays, in a network. A typical public transport travel time between one centroid and another consists of four elements—a walking time to the bus, tram or transit stop, a waiting time at the stop, an average riding time on the transport vehicle and a walking time to the ultimate destination.

TRIP

A one-way movement from one place to another for a particular purpose. The term generally refers to movements using a powered conveyance. (See "linked trip" and "unlinked trip".)

TRIP END

The origin or destination of a trip.

TRIP MATRIX

A record of zone-to-zone trips, giving the numbers of trips in each direction between each pair of zones.

TRIP PURPOSE, PURPOSE

The main purpose or intention for which a trip is made, the fulfilment of which marks the end of the trip.

UNDERPIN

To provide new permanent support beneath a wall or column without removing the superstructure; the construction of new foundations for existing buildings.

UNLINKED TRIPS

A one-way movement from one place to another for a particular trip purpose by a particular mode of travel, as recorded on the home-interview form, and which is considered to be completed when either the trip purpose has been accomplished or a change in mode of travel has occurred. (See "Linked trip".)

URBAN AREA

Hong Kong Island, Kowloon and New Kowloon, the "survey area". All of the Colony except the "New Territories".