A TRAFFIC ASSIGNMENT PLANNING MODEL: THE LOAD-NODE CONCEPT
Abstract The use of the traffic assignment model in urban transportation planning is universal; however, traffic assignment in its present form is expensive, cumbersome, and has serious limitations. In this research the authors have developed and tested the load-node concept of traffic assignment which reduces many of these problems. In the load-node concept the corners of zone boundaries are used for points of trip origins and destinations. In this manner the zone centroids and associated connector linkages of the network are removed. This results in a substantial reduction in network coding. In this study the total number of nodes required to define the network decreased by almost 3000 to 995 and the number of links in the network decreased by two-thirds. The forecasted 1990 Phoenix metropolitan area was used to test this approach and the average link volumes of all-or-nothing capacity restraint assignments using both the load-node and zone centroid concepts formed the basis of the comparison. The analyses indicated the average link volumes of the two concepts are comparable. A probable reduction in computer time of 40 + per cent was obtained when the load-node concept was used. The authors suggest that this approach is primarily adaptable for planning purposes and not design. With respect to the design use of traffic assignment results, the travel between adjacent zones is seldom included in the major arterial street and freeway traffic volumes obtained from zone centroid assignment. This may result in a substantial underestimation of future traffic volume and turning movements particularly if stepped down 24-hr assignments are used for design purposes. The load-node approach does assign travel between adjacent zones.
An Investigation into Traffic Turning Movement at Jibowu
This paper aims at understanding the behavioral pattern of traffic at Jibowu intersection with a view of using the results obtained as a model for understudying traffic movement at similar intersections in the Lagos metropolis. Consequently, an evaluation of the sampled intersections was carried out by employing a physical measurement of the layout, traffic volume at each turning point, and evaluating it against the back drop of traffic delays at the intersections. The paper reviews the traffic flow situation within the context of increasing motorization, poor infrastructural facilities and a continuous stream of traffic inflow. It highlights the problems with emphasis on the importance of signalization, land use, intersection design and traffic systems management. The paper concludes that most of the bottlenecks experienced at the intersection are man-induced. Rather than obeying traffic regulations, people act otherwise either out of ignorance or gross indiscipline. Secondly the paper posits that the land use allocation in the area should be reviewed especially with emphasis on discouraging the luxury bus operators from using the area as their base or Main Park. Although the paper did not fully measure the delay at the intersection, it has however set the stage for further investigations.
Jet, Rocket, Nuclear, Ion and Electric Propulsion: Theory and Design
Jet, rocket, nuclear, ion, and electric propulsion; theory and design , Jet, rocket, nuclear, ion, and electric propulsion; theory and design , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی