- John Glen Wardrop
John Glen Wardrop was an English transport analyst who developed Wardrop's first and second principles of equilibrium.
The concepts are related to the idea of
Nash equilibriumin game theorydeveloped separately. However in transportation networks, there are many players, making the analysis more difficult than in games with small numbers of players.
In studies about traffic assignment, network equilibrium models are commonly used for the prediction of traffic patterns in transportation networks that are subject to congestion. The idea of traffic equilibrium originated as early as 1924, with
In 1952, Wardrop stated two principles that formalize this notion of equilibrium and introduced the alternative behavior postulate of the minimization of the total travel costs.
Wardrop's first principle of route choice, which is identical to the notion postulated by Knight, became accepted as a sound and simple behavioral principle to describe the spreading of trips over alternate routes due to congested conditions.
Wardrop's first principle states: "The journey times in all routes actually used are equal and less than those which would be experienced by a single vehicle on any unused route." Each user non-cooperatively seeks to minimize his cost of transportation. The traffic flows that satisfy this principle are usually referred to as "user equilibrium" (UE) flows, since each user chooses the route that is the best. Specifically, a user-optimized equilibrium is reached when no user may lower his transportation cost through unilateral action.
A variant on this is the
stochastic user equilibrium(SUE) wherein no driver can unilaterally change routes to improve his/her perceived travel times.
Wardrop's second principle states: "At equilibrium the average journey time is minimum." This implies that each user behaves cooperatively in choosing his own route to ensure the most efficient use of the whole system. Traffic flows satisfying Wardrop's second principle are generally deemed "system optimal" (SO). Economists argue this can be achieved with
marginal cost road pricing.
The first mathematical model of network equilibrium was formulated by Beckmann, McGuire and Winsten in 1956.
* Wardrop, J. G., 1952. Some theoretical aspects of road traffic research, "Proceedings, Institute of Civil Engineers", PART II, Vol.1, pp. 325-378.
Wikimedia Foundation. 2010.
Look at other dictionaries:
John Wardrop — may be:*John Glen Wardrop, English transport analyst *Sir John Oliver Wardrop (1864 ndash;1948), English diplomat … Wikipedia
Wardrop — may refer to:* James Wardrop (1782–1869), Scottish surgeon. * Marjory Wardrop (1869–1909), British literary scholar. * Oliver Wardrop (1864–1948), British diplomat. * John Glen Wardrop, British transport analyst … Wikipedia
Principe de wardrop — En mathématiques, le principe de Wardrop s énonce ainsi : pour chaque couple d origine–destination, les chemins utilisés ont le même coût généralisé et celui ci est inférieur aux coûts des chemins non utilisés. Si, pour un couple origine… … Wikipédia en Français
Principe de Wardrop — En mathématiques, le principe de Wardrop s énonce ainsi : pour chaque couple d origine–destination, les chemins utilisés ont le même coût généralisé et celui ci est inférieur aux coûts des chemins non utilisés. Si, pour un couple origine… … Wikipédia en Français
List of economists — This is an alphabetical list of notable economists, that is, experts in the social science of economics. There is also a separate list of politicians with economics training.A*Diego Abad de Santillán *Daron Acemoglu *Zoltan Acs *George Akerlof… … Wikipedia
Chapeltoun — Coordinates: 55°39′56″N 4°33′17″W / 55.66557°N 4.55484°W / 55.66557; 4.55484 … Wikipedia
1954 British Empire and Commonwealth Games — 5th British Empire and Commonwealth Games Host city Vancouver, British Columbia, Canada Nations participating 24 … Wikipedia
News International phone hacking scandal — Rupert Murdoch, chairman and chief executive officer of News Corporation, the parent company of News International The News International phone hacking scandal is an ongoing controversy involving mainly the News of the World but also other… … Wikipedia
New Year Honours 2008 — The New Year Honours 2008 for the Commonwealth Realms were announced on 29 December 2007, [cite web| url=http://news.bbc.co.uk/1/hi/uk/7163660.stm| title= Parkinson and Minogue top honours] to celebrate the year passed and mark the beginning of… … Wikipedia
2008 New Year Honours — The New Year Honours 2008 for the Commonwealth Realms were announced on 29 December 2007, to celebrate the year passed and mark the beginning of 2008. The recipients of honours are displayed here as they were styled before their new honour,… … Wikipedia