scholarly journals Mathematical Analysis for Roundabout Capacity

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Wonho Suh ◽  
Jung In Kim ◽  
Hyunmyung Kim ◽  
Joonho Ko ◽  
Young-Joo Lee

This paper investigates roundabout capacity analysis using mathematical modelling and microscopic simulation. The capacity in approach section in roundabout is calculated by estimating the number of vehicles that can enter a roundabout for a given approach given a certain circulating volume. Since roundabouts are working with only yield conditions, capacity is dependent on gap acceptance model. Priority rules are used to simulate the gap acceptance model and define the right-of-way for conflicting movements. In the case of roundabouts, priority rules can be utilized to establish right-of-way at each of the conflict points where the approach traffic merges with the circulating traffic of the roundabout. By altering the minimum acceptable gap and related parameters, it is possible to calibrate a simulation model to be that of a real-life roundabout or that of a theoretical roundabout that meets the operating characteristics defined in current capacity models. The proposed roundabout capacity analysis methodology is expected to assist modelling operational conditions for roundabouts. Results are presented that provide evidence to validate the proposed approach.

2008 ◽  
Vol 35 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Jin-Tae Kim ◽  
Joonhyon Kim ◽  
Myungsoon Chang

Existing techniques for microscopic simulation of lane changes utilize a single critical gap for a single vehicle. Freeway merging areas have been among the most difficult aspects of simulations due to the wide variety of merging behaviors in these areas. This paper proposes a gap acceptance model developed to update the size of the critical trailing gap for a merging vehicle during simulation based on the location of the vehicle in an acceleration lane. It also considers the relative speed and critical leading gap. Sets of critical trailing gap values for various situations are computed. The outputs from the microscopic simulations utilizing the proposed model were compared with field data, producing strong statistical evidence that the simulation results and field data were significantly comparable.


2018 ◽  
Vol 48 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Doddapaneni Abhigna ◽  
Dipak P. Brahmankar ◽  
Kodavanti Venkata Raghavendra Ravishankar

Intersections are the critical zones where conflicting, merging and diverging movements influence the intersection capacity. Uncontrolled intersections in particular pose dangerous situations to vehicular traffic. During peak vehicular flow, the unpredictable crossing behavior of minor stream vehicles induces delay and reduces the capacity of the intersection. Capacity at uncontrolled intersections is typically measured either by gap acceptance method, empirical regression approaches and conflict technique. Gap acceptance is an important characteristic for analyzing uncontrolled intersections. The behavior of different vehicle types and gap of subject vehicle type from minor street taking right turn to merge with major traffic stream is analyzed using gap acceptance method. The objective of the current study is to analyze the effect of major stream vehicle type combinations on the minor stream vehicle gap-acceptance behavior and to determine the capacity of the minor stream taking into account the influence of the right turning vehicles. The capacity of minor stream calculated using Highway Capacity Manual (HCM) 2010, Luttenin’s model, and Tanner’s model are compared. It is observed that two wheelers are more aggressive than three wheelers for most of the major stream vehicular combinations observed in this study.


Author(s):  
Nataliia Kharytonova ◽  
Olha Mykolaienko ◽  
Tetyana Lozova

Greening of roads contributes to the protection of roads and their elements from influence of adverse weather and climatic factors; it includes the measures for improvement and landscaping of roads, ensures the protection of roadside areas from transport pollution, provides visual orientation of drivers. The solution of these issues will ensure creation and maintenance of safe and comfortable conditions for travelers. Green plantings in the right-of-way road area include woody, bushy, flower and grass vegetation of natural and artificial origin. For proper operation of public roads and satisfaction of other needs of the industry, there may be the need in removing the greenery. The reason for the removal of greenery in the right-of-way road area may be due to the following factors: construction of the architectural object, widening of the motor road, repair works in the security zone of overhead power lines, water supply, drainage, heating, telecommunications facilities, cutting of hazardous, dry and fautal trees, as well as self-grown and brushwood trees with a root neck diameter not exceeding 5 cm, elimination of the consequences of natural disasters and emergencies. The removal of plantations in the right-of-way area is executed in order to ensure traffic safety conditions and to improve the quality of plantations composition and their protective properties. Nowadays, in Ukraine there is no clear procedure for issuing permits for removing of such plantations. In order to resolve this issue, there is a need in determining the list of regulations in the area of forest resources of Ukraine and, if needed, the list of regulatory acts that have to be improved; to prepare a draft of the regulatory legal act that would establish the procedure of plantations cutting, the methodology of their condition determination, recovery costs determination, the features of cutting. Keywords: plantations, cutting, right-of-way, woodcutting permit, order.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meir Meshulam ◽  
Liat Hasenfratz ◽  
Hanna Hillman ◽  
Yun-Fei Liu ◽  
Mai Nguyen ◽  
...  

AbstractDespite major advances in measuring human brain activity during and after educational experiences, it is unclear how learners internalize new content, especially in real-life and online settings. In this work, we introduce a neural approach to predicting and assessing learning outcomes in a real-life setting. Our approach hinges on the idea that successful learning involves forming the right set of neural representations, which are captured in canonical activity patterns shared across individuals. Specifically, we hypothesized that learning is mirrored in neural alignment: the degree to which an individual learner’s neural representations match those of experts, as well as those of other learners. We tested this hypothesis in a longitudinal functional MRI study that regularly scanned college students enrolled in an introduction to computer science course. We additionally scanned graduate student experts in computer science. We show that alignment among students successfully predicts overall performance in a final exam. Furthermore, within individual students, we find better learning outcomes for concepts that evoke better alignment with experts and with other students, revealing neural patterns associated with specific learned concepts in individuals.


Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4141
Author(s):  
Wouter Houtman ◽  
Gosse Bijlenga ◽  
Elena Torta ◽  
René van de Molengraft

For robots to execute their navigation tasks both fast and safely in the presence of humans, it is necessary to make predictions about the route those humans intend to follow. Within this work, a model-based method is proposed that relates human motion behavior perceived from RGBD input to the constraints imposed by the environment by considering typical human routing alternatives. Multiple hypotheses about routing options of a human towards local semantic goal locations are created and validated, including explicit collision avoidance routes. It is demonstrated, with real-time, real-life experiments, that a coarse discretization based on the semantics of the environment suffices to make a proper distinction between a person going, for example, to the left or the right on an intersection. As such, a scalable and explainable solution is presented, which is suitable for incorporation within navigation algorithms.


1985 ◽  
Vol 61 (1) ◽  
pp. 222-222
Author(s):  
John Trinkaus
Keyword(s):  

2000 ◽  
Author(s):  
Stephen J. Kokkins ◽  
S. Kash Kasturi ◽  
Wayne Kong ◽  
S. K. John Punwani

Abstract Representative structural models of locomotives, other rail vehicles, and other potential colliding objects were combined into moving consists which were then subjected to various collision scenarios. The LS-DYNA dynamic finite-element modeling code was utilized to realistically simulate collisions and guide understanding and improvements of the locomotive structures. This incorporated the effects of the collision interactions, plus critical non-linear material and structural behavior, buckling, fracture, kinematics, and wayside interactions of the vehicles. The types of collisions included: locomotive-headed consists striking standing consists obliquely fouling the Right Of Way, headed both by freight cars and other locomotives; locomotives striking loose, loaded intermodal containers dislodged from opposing cars on adjacent track. Work on multiple coupled locomotive overrides in direct consist collisions is now being conducted. The effects of varying parameters such as collision speeds, location and orientation of the colliding vehicles, and structural improvements were explored and quantified. Also, the effects of some structural design modifications such as stronger collision posts and cab structure were evaluated using this process. Verification studies to date have shown good correlation between the analytical simulations and observed outcome of actual historical accidents.


2017 ◽  
Vol 25 (2) ◽  
pp. 5-19
Author(s):  
Agnieszka Bieda ◽  
Anita Kwartnik-Pruc ◽  
Edyta Puniach

Abstract Large-format advertisements are becoming a more and more common element of building facades, especially in city centers. Placing an object of this type is not without significance to the real property management. A large-format advertising billboard on the facade, on the one hand, is associated with the possibility of renting advertising space, on the other - it can lead to the occupancy of a right-of-way, which results in a necessity to pay appropriate fees, in the amount regulated by the Act on Public Roads. Placing an object such as a large-format advertising billboard in a right-of-way requires a permit of the manager of this road. However, if a billboard is located on the facade of a building, occupancy of the right-of-way is not always the case. If the boundary of the road parcel runs along the contour of the building, a billboard placed on the elevation will always occupy the right-of-way. However, property boundaries often run at a distance from the building. Such situations - desired by managers - result in a noticeable increase in demand for surveying opinions to determine what part of the right-of-way is occupied by a large-format advertisement. This article analyzes the cases of the right-of-way being occupied by large-format advertising placed on the facades of buildings in the city center. For selected objects, information was obtained from public records, National Cartographic Documentation Center database, and direct surveying was performed with various techniques. This allowed for an objective assessment of the possible use of available surveying methods and the acquired spatial data to determine the right-of-way occupied by large-format advertisements for purposes of real estate management.


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