Traffic Roundabouts Research Articles

Nicaragua 1996–2001

Katherine Isbester received her PhD from the University of Toronto in 1996. Her book, Still Fighting: The Nicaraguan Women's Movement 1977-2000, was recently published by the University of Pittsburgh Press.NICARAGUAN POLITICS, which received so much coverage during the 1980s, has received precious little since. Recently, however, the media silence has been broken. Nicaragua began to receive international attention once again when Daniel Ortega announced his intention to run for the presidency in the election of 4 November 2001. The possibility of the return of a man with historic links to Middle Eastern terrorist nations, as the American government reminded Nicaraguans, prompted a high level of diplomatic intervention.Perhaps the flurry of diplomatic activity was unnecessary. The Ortega of today and his party, the Sandinista Front for National Liberation (FSLN), have changed in their decade out of power. To have a chance at re-election, Ortega and the FSLN altered their fundamental orientation from supporting the poor to co-operating with the Nicaraguan elite at the same time as they capitalized on its divisions. This article analyzes how the outgoing government, the American-backed right-wing Liberal Alliance, divided the elite in Nicaragua and alienated the populace during the 1990s, thus paving the way for the re-emergence of Ortega and the FSLN. As a result of the FSLN remodelling itself and the Liberals underperforming, the election was too close to call.When the FSLN came to power through a popular revolution in 1979, it initiated a number of social justice programmes to help the disenfranchised and the poor, fought an American-backed counter-revolutionary civil war, and nationalized parts of the economy. It also implemented an agrarian reform programme. Despite these muchlauded policies, it was democratically voted out of power in 1990.The Nicaraguan populace opted for right-wing American-approved governments that promised peace with the United States and economic prosperity. Since the FSLN were voted out of office, there have been two such governments. The National United Opposition (UNO), led by Violeta Chamorro, lasted from 1990 to 1996. It oversaw Nicaragua's transition to a capitalist economy integrated into the global market through structural adjustment programmes, the professionalization of the army, the finalization of peace with the counter-revolutionary forces, and an inter-party agreement over property ownership. Nonetheless, the standard of living for the vast majority of the populace fell, violence in the form of re-armed militias increased, and governance ground to a halt in 1994. As a result, Nicaraguans doubted the ability of democratic institutions to improve their lives. On the brink of social, political, and economic chaos, in the 1996 presidential elections they chose a neo-populist(1) strongman, Arnoldo Aleman of the Liberal Alliance.Aleman, a lawyer who represented banks and other commercial enterprises before the 1979 revolution, came from a family of staunch supporters of the dictatorship. His property, like that of all those who had been closely affiliated with the dictator, Somoza, was seized by the FSLN, and Aleman was jailed and released. Nonetheless, he remained in Nicaragua through the 1980s increasing his land holdings. In 1990, he was elected to Managua's city council and manoeuvred to become mayor, a position he held until he became president in 1996. While in office, he beautified the city by installing fountains and traffic round-abouts, planting trees, and knocking down crumbling buildings. These programmes were remarkably popular even among the poor and made a visible - if superficial - difference to the city. Throughout his tenure, Aleman publicized how much he was able to accomplish compared to the stalemated National Assembly. During his election campaign, he promised the same modernization treatment for the country. Funded by the Nicaraguan elite and American expatriates, including the rich expatriate Cuban-American community, Aleman won the election. …

Traffic performance analysis at roundabouts

This paper considers the problem of estimating traffic performance characteristics at traffic roundabouts. One and two lane roundabouts are considered with the results consisting of analytical expressions for capacity, queue length, and delay. Where drivers have a choice of lane for a manoeuvre, a user optimal model is used to allocate flow to alternative lanes. The analysis is suitable for inclusion in traffic assignment models which explicitly represent traffic conflicts at intersections, or in stand-alone analytically based computer programs which analyse a single roundabout.

Noise levels in the vicinity of traffic roundabouts

An experimental procedure for analyzing roundabout noise is described. Measurement of the noise from accelerating and decelerating traffic streams on the approach roads to roundabouts at a total of 70 positions at three sites are reported together with a simulation study of noise from central island traffic. The results show that, in general, noise from the accelerating traffic streams is within ±1 dB(A) of the free flow level on the same road and that the noise from the decelerating stream is equal to or less than the free flow level. The propagation of noise from the central island is expressed in the form of a nomogram. Good agreement between predicted and measured levels was found.