Showing papers on "Traffic wave published in 1983"

Calibration of transyt platoon dispersion model for passenger cars under low-friction traffic flow conditions (abridgment)

Abstract: The calculation of delay and stops by the TRANSYT program and in turn the effectiveness of the signal timings resulting from its optimization procedure depend on the ability of its platoon dispersion model to accurately predict traffic flow patterns from one signal to another. Therefore, calibration of the dispersion factor alpha and travel-time factor beta in the model is important to the successful implementation of the TRANSYT program. However, because of limited research, a definitive description of the relationship between the appropriate values of alpha and beta and roadway conditions does not exist. The objective of this research was to contribute to the ultimate development of a definitive description of this relationship by calibrating this model for passenger cars under low-friction traffic flow conditions. Platoon dispersion studies were conducted on six arterial street segments (2 two-way two-lane segments and 4 four-lane divided segments). Traffic flow patterns of nearly 1700 platoons were analyzed. The results indicated that less platoon dispersion was observed in this study than has been found in other studies of low-friction traffic flow conditions. It was concluded that appropriate values of alpha and beta for passenger cars under these conditions are alpha equal to 0.21 and beta equal to 0.97 on two-way two-lane streets and alpha equal to 0.15 and beta equal to 0.97 on four-lane divided streets. (Author)

Stochastic processes in freeway traffic part ii. incident detection algorithms

Abstract: Part I of this two-part series of papers addressed the problem of constructing stochastic process models for freeway traffic and examined the robustness of these models in providing short-term predictions of traffic state variables. In this part, an approach for the automatic detection of freeway traffic incidents (accidents, stalled vehicles, debris on the road, etc.) is presented based on the ARIMA (0,1,3) model described in Part I. Traffic incidents often result in full or partial lane blockage, and they occur most frequently during the peak periods when normal freeway capacity is already hard pressed. West found that the non-recurring congestion due to traffic incidents is responsible for as much motorist delay on urban freeways as is the recurring congestion due to geometric bottlenecks. Many freeway operating agencies, therefore have recognised the fact that incident management measures, if soundly based can permit greater traffic flows to be accommodated more safely on the existing freeway system with considerable savings in travel time to motorists.

Automation and control in transport. 2nd revised edition

Abstract: Although the author gives prominence to railway technology, some of the areas treated applies to both road and rail bound transport and some to road transport only. These areas are as follows: route capacity - laws for vehicle following (lane capacity, car-following theory, automatic vehicle systems), problems of congestion - traffic regulation (statistical aspects of car-following behaviour, traffic waves), computer aids to operation - traffic surveillance and control (split cycle and offset optimisation technique: scoot, control of cascaded vehicles), measurement of power - analogue computing (application to strings of vehicles), vehicle identification (bus electronic scanning indicator), interlocking - sequence control (control of intersections - automatic half barriers), control of acceleration and power (automatic transmissions), control of braking, steering - directional stability, some modern rapid transit lines (guided transport, recently constructed underground railways, intermediate systems, light electric vehicles - Tyne and Wear system, pneumatic-tired systems, innovative - fully automated systems), and possibilities for the future including small vehicles under computer control, intercity transport: high-speed rail, new forms of urban and intercity transport, air-cushion transport, linear induction motore, linear synchroneous motors, electro-magnetic support and guidance (attraction mode), magnetic support and guidance -the repulsion (electrodynamic) system, and some unexplored possibilities. (TRRL)

Stop and go urban intersection noise

Abstract: A summary of a procedure to predict stop and go urban intersection noise is presented. A computer program that takes into account the effects of urban building structures on multiple reflection and diffuse scattering; vehicle types, mixes, and traffic signalization on microscopic traffic flow behavior; and vehicle acceleration as well as speed and type of vehicle source strength is described. The concepts used in the acoustic model are summarized, and the principal simplifying assumptions in the numerical treatment are noted. The large number of options of street geometry caused by the presence or absence of building walls on any of the eight possible wall locations resulted in considerable program complexity, which was resolved by careful program structure and logic. A typical computer input-output is presented, and some preliminary results for a single vehicle passby are presented.

What makes a totally good railroad crossing

Abstract: A totally good rail-highway crossing is one that not only will provide safe riding qualities to trains and vehicle, but will be maintenance-free for the life of all components. It is not generally recognized that highway traffic shocks are what wear out the crossing, not rail traffic. This article discusses various design considerations for crossings, including drainage, foundations, wearing surfaces, track structure and others.

A preliminary study on the simulation of mixed traffic flow

Abstract: The traffic flow in the streets of Taiwan is characterized by a great number of motorcycles mixed with automobiles. This special phenomenon induces many traffic problems which can not be easily solved, and up till now no reliable method of analysis has been developed. After a long period of field observation, a method of simulating the behavior of mixed’ traffic flow has been formulated. This method is based on concepts introduced by the authors of the vehicle's possible leeway for progress as well as the maximum angle of deviation. The vehicles are moved within limits imposed by the width of the traffic lane and the preceding traffic. Finally, some aspects of the method which could be improved by further research are discussed.

The sensitivity of the hydrodynamic theory of traffic flow to macroscopic traffic model forms, with particular application to optimal traffic control at oversaturated intersections

Abstract: 2. When an image on the film is obliterated w ith a round black mark, it is an indication o f either blurred copy because o f movement during exposure, duplicate copy, o r copyrighted materials that should not have been filmed. For blurred pages, a good image o f the page can be found in the adjacent frame. I f copyrighted materials were deleted, a target note w ill appear listing the pages in the adjacent frame.