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Showing papers on "Traffic wave published in 1990"


Journal Article
TL;DR: In this paper, vehicles are organized in platoons in which the lead car is manually driven and the other cars are under automatic spacing (headway) control, and a plausible model of the resulting flow of traffic indicates that, for an average platoon size of 20, the capacity of the freeway increases by a factor of four.
Abstract: The following two proposals are presented: (1) Vehicles are organized in platoons in which the lead car is manually driven and the other cars are under automatic spacing (headway) control. A plausible model of the resulting flow of traffic indicates that, for an average platoon size of 20, the capacity of the freeway increases by a factor of four. (2) A macroscopic model of freeway traffic congestion along with a control law for reducing congestion is presented. Simulation of the resulting closed loop model indicates a dramatic reduction in congestion.

49 citations


Journal ArticleDOI
TL;DR: An algorithm for estimating crash times under various traffic shocks is derived, and an algorithm for crash time estimation of a G/D/1 link model is derived using a different (perturbation-analysis-based) approach.
Abstract: Efficient techniques for estimating performance measures in communication networks in a steady-state or transient setting are developed. These techniques may be used in a simulation environment or in connection with real-time observations. For Markov chain models, the recently proposed standard clock approach is extended, and a class of real-time algorithms for simultaneously generating multiple sample paths under different parameter sets is presented. Attention is focused on the link crash time estimation problem, where a 'crash' is defined as the first time a buffer overflows, given some initial conditions. An algorithm for estimating crash times under various traffic shocks is derived, where all estimates are obtained in parallel to an actual network's normal operation. An algorithm for crash time estimation of a G/D/1 link model is also derived using a different (perturbation-analysis-based) approach. Finally, extensive simulation results are provided to validate the proposed algorithms and compare them to brute-force simulation. >

26 citations




Journal ArticleDOI
TL;DR: This paper investigates the control problem of choosing suitable speed values, with the aim of reducing the probability of congestion and presents a model for freeway traffic that performs realistically in several basic traffic situations.

3 citations


01 Jan 1990
TL;DR: Guidelines for determining the number and length of left-turn lanes needed at signalized intersections have been developed and equivalence factors for converting right-turn traffic volumes to equivalent straight-through volumes at stop-sign controlled intersections are presented.
Abstract: The capacity of an intersection is affected significantly by the relative proportion of straight-through and turning vehicles in each approaching lane. In many situations - particularly at signalized intersections - traffic throughput on an approach can be increased by adding auxiliary lanes to accommodate only turning vehicles. Techniques for designing left-turn and right-turn lanes at intersections and evaluating the related traffic performance are needed. Guidelines for determining the number and length of left-turn lanes needed at signalized intersections have been developed. The guidelines are implemented primarily through a microcomputer program called "Left-Turning Movement Analysis Program" (LTMAP). This program provides the engineer/user with an interactive means for entering descriptive data concerning intersection turn- lane configuration, traffic volumes, vehicle classes, traffic behavior parameters, and signal timing. A range of descriptive quantitative information about expected queue lengths, likely signal-cycle failures, volume-to-capacity statistics, and various delay estimates is produced immediately by the program. Different intersection operational situations can be compared quickly and easily in this way. Equivalence factors for converting right-turn traffic volumes to equivalent straight-through volumes at stop-sign controlled intersections are presented, and guides for determining the length of right-turn bays at a signalized intersection are shown graphically. These tools aid the engineer in designing and analyzing auxiliary-lane treatments required for various intersection conditions.

2 citations


Journal Article
TL;DR: The characteristics of the link are modified to account for delay caused by queuing: as traffic is assigned to the link, its constrained speed drops at a faster rate than if it had no control device, and the constrained speeds on controlled links were also found acceptable.
Abstract: In a sub-area network, stop signs and signals at intersections can be a significant influence on travel paths. The presence of such devices often must be simulated in computerized highway networks so as to obtain more realistic assignments. One common way of doing this is to use "turn penalties." This is very resource-intensive, and has been known to confuse the path-building logic of some programs, resulting in poor assignments. An alternative method has been developed to avoid these problems. This method is based on theoretical models of delay, as a function of the V/C ratio of the controlled approach. Given the link's distance, the uncontrolled free speed, and the type of control device, a new "zero-volume" link speed and capacity are calculated to account for the delay induced by the control device. Further, the characteristics of the link are modified to account for delay caused by queuing: as traffic is assigned to the link, its constrained speed drops at a faster rate than if it had no control device. A county-wide travel demand model using this technique was implemented using MINUTP, and the control device simulation method was applied with a FORTRAN program which modifies the speed and capacity of controlled links. A comparison of assigned volumes to ground counts by control device type showed reasonable results, and the constrained speeds on controlled links were also found acceptable.

1 citations


Journal ArticleDOI
TL;DR: From the computer simulation results of Route 2 national main road in Fukuyama city, it is confirmed that the feedback control method of traffic congestion lengths at 2-adjacent signalized intersections proposed here is actually effective.

1 citations


Journal ArticleDOI
TL;DR: A new method for detection and measurement of the dilemma state is described, and results of field trials carried out at three locations representative of typical traffic conditions in Japan are presented.