Cyd-destun: traffig. Ymddengys yn glir o'r diffiniadau isod fod 'tagfeydd
traffig' ddim yn gwneud y tro o gwbl. Tybed oes rhyw economegydd,
peiriannydd sifil, neu ddaearyddwr caredig yn medru awgrymu rhywbeth cywir,
clir a bachog?
Tim
A situation when too many people or vehicles are trying to use the same
facilities for them to work with maximum efficiency. This may result in a
fall in the quality or quantity of services provided. Congestion is a source
of external diseconomies: while drivers on crowded roads, for example, are
themselves inconvenienced, a cost they bear themselves, they also cause
delay, higher fuel costs, and a greater chance of accidents to other road
users.
A Dictionary of Economics. John Black. Oxford University Press, 2002.
A general term in economics for the degradation or additional cost imposed
by the overuse of a service or facility-classically, the highways.
Congestion occurs under conditions where pricing is lower than the costs
imposed, often when property rights are not well defined. The economic
analysis of congestion seeks to design policy measures that minimize such
costs (e.g., the design of highway tolls) and plays an important role in
public-policy arenas.
Dictionary of the Social Sciences. Craig Calhoun, ed. Oxford University
Press 2002.
The restriction of the use of a facility by over-use. The term is generally
used to indicate the slowing of urban traffic because too many vehicles are
competing for too little space, but it can be applied to any excessive
demand for any facility, when use exceeds carrying capacity. Congestion on a
routeway depends on the carrying capacity of the route, the volume of
traffic, and the varying proportions of the total freight and passenger
traffic carried by competing means of transport (the modal split). The
effects of congestion involve long, frustrating, and often costly, delays,
road accidents, air pollution, and noise, all of which create an externality
to the urban economy. They are, however, difficult to quantify in terms of
cost and the individual may have little control over them.
A Dictionary of Geography. Susan Mayhew. Oxford University Press, 1997.
Oxford Reference Online.
|