Effective Measures to Restrict Vehicle Turning Movements

2017 ◽  
Vol 2638 (1) ◽  
pp. 45-54
Author(s):  
Karen K. Dixon ◽  
Raul E. Avelar ◽  
Yanfen Zhou
Keyword(s):  
Transportation Network ◽  
Access Point ◽  
Left Turns ◽  
Operational Impacts ◽  
Turn Restrictions ◽  
Significant Conflict

This study evaluated alternatives to raised and nontraversable medians on driveways and approaches. Raised medians are often effective for limiting direct left turns at significant conflict points. Raised medians also improve corridor aesthetics. This research reviewed a variety of turn restrictions to determine how effectively they address the operational needs of the transportation network while addressing contextual sensitivities. The turn restrictions evaluated in the study were separated into three broad categories: turn restrictions located only at the access point, turn restrictions located only in the roadway (typically some type of median configuration), and combined turn restriction configurations. Field evaluations in Oregon and Texas were performed to determine the effectiveness of various turn restriction configurations. In addition, microsimulation evaluations were used to identify the operational impacts of the various turn maneuver restrictions.

Identification of Optimal Left-Turn Restriction Locations using Heuristic Methods

2021 ◽  
pp. 036119812110116
Author(s):  
Murat Bayrak ◽  
Vikash V. Gayah
Keyword(s):  
General Pattern ◽  
Complex Problem ◽  
Heuristic Solution ◽  
Left Turn ◽  
Grid Networks ◽  
Solution Algorithms ◽  
Starting Point ◽  
Left Turns ◽  
The Many ◽  
Turn Restrictions

Restricting left turns throughout a network improves overall flow capacity by eliminating conflicts between left-turning and through-moving vehicles. However, doing so requires vehicles to travel longer distances. Implementing left-turn restrictions at only a subset of locations can help balance this tradeoff between increased capacity and longer trips. Unfortunately, identifying exactly where these restrictions should be implemented is a complex problem because of the many configurations that must be considered and interdependencies between left-turn restriction decisions at adjacent intersections. This paper compares three heuristic solution algorithms to identify optimal location of left-turn restrictions at individual intersections in perfect and imperfect grid networks. Scenarios are tested in which restriction decisions are the same for all intersection approaches and only the same for approaches in the same direction. The latter case is particularly complex as it increases the number of potential configurations exponentially. The results suggest all methods tested can be effectively used to solve this problem, although the hybrid method proposed in this paper appears to perform the best under scenarios with larger solution spaces. The proposed framework and procedures can be applied to realistic city networks to identify where left-turn restrictions should be implemented to improve overall network operations. Application of these methods to square grid networks under uniform demand patterns reveal a general pattern in which left turns should be restricted at central intersections that carry larger vehicle flows but allowed otherwise. Such findings can be used as a starting point for where to restrict left turns in more realistic networks.

1899: Percutaneous Nephrostolithotomy: Impact of Access Point Number and Location on Complications

2004 ◽  
Vol 171 (4S) ◽  
pp. 502-502 ◽  
Author(s):  
Brian R. Matlaga ◽  
Steve J. Hodges ◽  
Ojas Shah ◽  
Dean G. Assimos
Keyword(s):  
Access Point ◽  
Percutaneous Nephrostolithotomy ◽  
Point Number

Investigating the Analysis of Power Saving Mode in IEEE 802.11 for Wi-Fi Communication

2018 ◽  
Vol 6 (3) ◽  
pp. 13-19
Author(s):  
Isam Aameer Ibrahim ◽  
Haider TH Salim ◽  
Hasan F. Khazaal
Keyword(s):  
Ieee 802.11 ◽  
Network Performance ◽  
Power Saving ◽  
Packet Delay ◽  
Access Point ◽  
Battery Life ◽  
Global Issues ◽  
Time Ratio ◽  
Power Saving Mode ◽  
Saving Mode

One of the major global issues today is energy consumption. Consequently, power management was introduced in various communication technologies. For IEEE 802.11wireless communication, there is a Power Saving Mode scheme (PSM) for increase the battery life of cell phone. In this PSM, there are two key parameters: beacon period interval (BI) and listen interval(LI). In most work these values are chosen arbitrary. Here, a scheme to determine the optimal BI and LI for accomplishing the most astounding conceivable vitality proficiency is introduced. This is implemented with the application of a numerical sample to the standard IEEE 802.11 PSM and Access Point-PSM (AP-PSM) schemes. To ensure the quality of network performance analysis on the normal and change of parcel delays is doing. The well-known queuing (M/G/I) model with bulk services are utilized. After the implementation of the proposed analysis, “maximum rest plan time ratio optimal Sleep Scheme (OSS)” which is when participate stations stay in the doze mode it can be determined. In this research shows that the optimal BI and LI produce optimal OSS time ratio scheme also achieved optimal average and variance of packet delay.

Best Neighbor Heuristic Search for Finding Minimum Paths in Transportation Networks

1998 ◽  
Vol 1651 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Jeffrey L. Adler
Keyword(s):  
Heuristic Search ◽  
Transportation Networks ◽  
Transportation Network ◽  
Search Problems ◽  
A Algorithm ◽  
Running Time ◽  
Search Effort ◽  
Wide Range ◽  
Path Search ◽  
Sparse Networks

For a wide range of transportation network path search problems, the A* heuristic significantly reduces both search effort and running time when compared to basic label-setting algorithms. The motivation for this research was to determine if additional savings could be attained by further experimenting with refinements to the A* approach. We propose a best neighbor heuristic improvement to the A* algorithm that yields additional benefits by significantly reducing the search effort on sparse networks. The level of reduction in running time improves as the average outdegree of the network decreases and the number of paths sought increases.

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