scholarly journals Velocity Obstacle Based Conflict Avoidance in Urban Environment with Variable Speed Limit

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 93
Author(s):  
Marta Ribeiro ◽  
Joost Ellerbroek ◽  
Jacco Hoekstra
Keyword(s):  
Conflict Resolution ◽  
Conflict Detection ◽  
Fast Time ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Package Delivery ◽  
Learning Agent ◽  
Variable Speed Limits ◽  
Conflict Detection And Resolution ◽  
Velocity Obstacle

Current investigations into urban aerial mobility, as well as the continuing growth of global air transportation, have renewed interest in conflict detection and resolution (CD&R) methods. The use of drones for applications such as package delivery, would result in traffic densities that are orders of magnitude higher than those currently observed in manned aviation. Such densities do not only make automated conflict detection and resolution a necessity, but will also force a re-evaluation of aspects such as coordination vs. priority, or state vs. intent. This paper looks into enabling a safe introduction of drones into urban airspace by setting travelling rules in the operating airspace which benefit tactical conflict resolution. First, conflicts resulting from changes of direction are added to conflict resolution with intent trajectory propagation. Second, the likelihood of aircraft with opposing headings meeting in conflict is reduced by separating traffic into different layers per heading–altitude rules. Guidelines are set in place to make sure aircraft respect the heading ranges allowed at every crossed layer. Finally, we use a reinforcement learning agent to implement variable speed limits towards creating a more homogeneous traffic situation between cruising and climbing/descending aircraft. The effects of all of these variables were tested through fast-time simulations on an open source airspace simulation platform. Results showed that we were able to improve the operational safety of several scenarios.

scholarly journals Homogenization Effects of Variable Speed Limits

2014 ◽  
Vol 15 (2) ◽  
pp. 130-143 ◽  
Author(s):  
Alvaro Garcia-Castro ◽  
Andres Monzon
Keyword(s):  
Weather Conditions ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Speed Limits ◽  
Key Indicator ◽  
Variable Speed Limits ◽  
Performance And Emissions ◽  
Speed Management ◽  
Road Performance

Abstract Changing factors (mainly traffic intensity and weather conditions) affecting road conditions require a suitable optimal speed at any time. To solve this problem, variable speed limit systems (VSL) - as opposed to fixed limits - have been developed in recent decades. This term has included a number of speed management systems, most notably dynamic speed limits (DSL). In order to avoid the indiscriminate use of both terms in the literature, this paper proposes a simple classification and offers a review of some experiences, how their effects are evaluated and their results This study also presents a key indicator which measures the speed homogeneity and a methodology to obtain the data based on floating cars and GPS technology applying it to a case study on a section of the M30 urban motorway in Madrid (Spain). It also presents the relation between this indicator and road performance and emissions values.

A PARALLEL ARCHITECTURE FOR AI NONLINEAR PLANNING

1990 ◽  
Vol 04 (02) ◽  
pp. 215-232 ◽  
Author(s):  
SUKHAN LEE ◽  
KYUSIK CHUNG
Keyword(s):  
Conflict Resolution ◽  
Distributed Processing ◽  
Parallel Architecture ◽  
State Level ◽  
Conflict Detection ◽  
Parallel And Distributed Processing ◽  
Resource Level ◽  
Planning Algorithm ◽  
Conflict Detection And Resolution ◽  
Nonlinear Planning

This paper presents a resource-level conflict detection and conflict resolution scheme which is combined with a state-level backward planning algorithm and provides efficient conflict detection and global conflict resolution for nonlinear planning. The scheme keeps track of the usage of individual resources during planning, and constructs a Resource-Usage Flow (RUF) structure (based on which conflict detection and resolution is accomplished). The RUF structure allows the system to perform minimal and nonredundant operations for conflict detection and resolution. Furthermore, resource-level conflict detection and resolution facilitates problem decomposition in terms of resources, thereby providing easy implementation in a parallel and distributed processing environment. Performance analysis indicates that the proposed architecture has a speed-up factor of the average depth of a plan network, D(Na), compared to the distributed NOAH, where Na (the total number of action nodes at the completion of planning) and D(Na) are considerably larger than the number of resources involved in planning as well as the number of initial goal states.

Use of Portable and Dynamic Variable Speed Limits in Construction Zones

2018 ◽  
Vol 2672 (16) ◽  
pp. 35-45
Author(s):  
Josh Van Jura ◽  
David Haines ◽  
Andrew Gemperline
Keyword(s):  
Intelligent System ◽  
Speed Limit ◽  
Department Of Transportation ◽  
Variable Speed ◽  
Construction Work ◽  
Work Zones ◽  
Dynamic Variable ◽  
Variable Speed Limit ◽  
Speed Limits ◽  
Variable Speed Limits

The Utah Department of Transportation (UDOT) implemented dynamic management of portable variable speed limit (PVSL) technology to reduce regulatory speed limits through an active work space (AWS). UDOT also developed and tested an intelligent system approach to alter speed limits in construction work zones. The goal of the PVSL system was to provide a portable and dynamic system that was easy for construction personnel to use to prudently reduce speeds within an AWS and make construction work zones safer for workers and the traveling public, while limiting the need to reduce speed throughout the AWS, rather than the entire construction work zone. This was achieved through temporary regulatory reductions in driver speeds within the immediate boundary of an AWS when workers were on site and exposed to the danger of errant vehicles during active construction. The system also raises speed limits when workers were not present. This PVSL system used a dynamic variable speed limit (VSL) algorithm to raise and lower the regulatory speed limits. The PVSL system also provided a queue warning algorithm that operated independent of the VSL algorithm to control messages posted on the portable variable message sign (PVMS) trailers to disseminate dynamic information to drivers. UDOT has completed 2 years of PVSL system deployment testing in four separate construction work zones to evaluate the effectiveness of the system. This paper highlights key elements that guided development of the PVSL system, along with the successful results from deployment of the system.

scholarly journals Review of Conflict Resolution Methods for Manned and Unmanned Aviation

Aerospace ◽  
2020 ◽  
Vol 7 (6) ◽  
pp. 79
Author(s):  
Marta Ribeiro ◽  
Joost Ellerbroek ◽  
Jacco Hoekstra
Keyword(s):  
Conflict Resolution ◽  
Air Transportation ◽  
Fast Time ◽  
Simulation Platform ◽  
Distributed Framework ◽  
Conflict Detection And Resolution ◽  
New Research ◽  
New Applications ◽  
Test Scenarios ◽  
Control Trajectory

Current investigations into urban aerial mobility, as well as the continuing growth of global air transportation, have renewed interest in Conflict Detection and Resolution (CD&R) methods. With the new applications of drones, and the implications of a profoundly different urban airspace, new demands are placed on such algorithms, further spurring new research. This paper presents a review of current CR methods for both manned and unmanned aviation. It presents a taxonomy that categorises algorithms in terms of their approach to avoidance planning, surveillance, control, trajectory propagation, predictability assumption, resolution manoeuvre, multi-actor conflict resolution, considered obstacle types, optimization, and method category. More than a hundred CR methods were considered, showing how most work on a tactical, distributed framework. To enable a reliable comparison between methods, this paper argues that an open and ideally common simulation platform, common test scenarios, and common metrics are required. This paper presents an overview of four CR algorithms, each representing a commonly used CR algorithm category. Both manned and unmanned scenarios were tested, through fast-time simulations on an open-source airspace simulation platform.

Numerical Simulation of Traffic Flow in the Tollgate Area with Variable Speed Limits

2011 ◽  
Vol 130-134 ◽  
pp. 3404-3409
Author(s):  
Wen Xing Zhu ◽  
Zhi Ping Jia
Keyword(s):  
Traffic Flow ◽  
Velocity Model ◽  
Flow Speed ◽  
Open Boundary ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Speed Limits ◽  
Optimal Velocity ◽  
Variable Speed Limits

We investigate behaviors of vehicles passing a controlled area with variable speed limits (VSL) before a tollgate. The traffic flow mathematical model is formulated based on optimal velocity model. The typical sketch of tollgate area is plotted and variable speed limit signs are set in the area to control the traffic flow speed for fear of accident and congestion. Simulations are carried out to examine the influence on traffic flow passing the controlled area with different number of the speed limit signs under open boundary condition. The simulations results show that more speed limit signs may reduce the risk of rear-end collision and the occurrence of the congestion in the tollgate area.

Driver Acceptance of Weather-Controlled Road Signs and Displays

1997 ◽  
Vol 1573 (1) ◽  
pp. 72-75 ◽  
Author(s):  
Pirkko Rämä ◽  
Juha Luoma
Keyword(s):  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Road Signs ◽  
Road Sign ◽  
Road Section ◽  
Variable Speed Limits ◽  
Road Condition ◽  
Driver Acceptance ◽  
Local Weather

This study was designed to investigate driver acceptance of the weather-controlled road signs and displays on Finland’s southern coast where road condition changes are particularly frequent and rapid. There were 36 variable speed limit signs and five variable message displays to warn about hazardous conditions on the 14-km-long experimental road section. Local weather and road surface conditions were monitored automatically from road weather stations; the information gathered was used for determining appropriate speed limit, as well as for controlling variable slippery road signs and temperature displays. Five hundred ninety drivers were interviewed 3, 4, 11, and 13 months after the introduction of this new road section. The results showed that drivers recalled the variable signs very well. Furthermore, 81 percent of the drivers said that the posted speed limit was appropriate, and 95 percent of the drivers stated that the variable speed limits were useful. However, only a relatively small proportion of drivers estimated that the slippery road sign or temperature display influenced their behavior. The main implication of this study is that the concept of the weather-controlled road signs and displays is a promising one. However, objective data will be collected in order to estimate the effects of the weather-controlled road signs and displays on driver behavior and to evaluate the profitability of the system.

Conflict Monitoring Across the Life Span

2014 ◽  
Vol 28 (3) ◽  
pp. 124-135 ◽  
Author(s):  
Daniela Czernochowski
Keyword(s):  
Older Adults ◽  
Life Span ◽  
Age Groups ◽  
Conflict Detection ◽  
Response Conflict ◽  
Conflict Monitoring ◽  
Subsequent Performance ◽  
Additional Control ◽  
Performance Response ◽  
Conflict Detection And Resolution

Errors can play a major role for optimizing subsequent performance: Response conflict associated with (near) errors signals the need to recruit additional control resources to minimize future conflict. However, so far it remains open whether children and older adults also adjust their performance as a function of preceding response conflict. To examine the life span development of conflict detection and resolution, response conflict was elicited during a task-switching paradigm. Electrophysiological correlates of conflict detection for correct and incorrect responses and behavioral indices of post-error adjustments were assessed while participants in four age groups were asked to focus on either speed or accuracy. Despite difficulties in resolving response conflict, the ability to detect response conflict as indexed by the Ne/ERN component was expected to mature early and be preserved in older adults. As predicted, reliable Ne/ERN peaks were detected across age groups. However, only for adults Ne/ERN amplitudes associated with errors were larger compared to Nc/CRN amplitudes for correct trials under accuracy instructions, suggesting an ongoing maturation in the ability to differentiate levels of response conflict. Behavioral interference costs were considerable in both children and older adults. Performance for children and older adults deteriorated rather than improved following errors, in line with intact conflict detection, but impaired conflict resolution. Thus, participants in all age groups were able to detect response conflict, but only young adults successfully avoided subsequent conflict by up-regulating control.

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