Development and Evaluation of a Green Wave Control Algorithm Based on Two-Way Bandwidth Maximization for Transit Signal Priority

2014 ◽  
Vol 505-506 ◽  
pp. 1046-1054 ◽  
Author(s):  
Liu Yi Gao ◽  
Xiao Jian Hu ◽  
Wei Wang ◽  
Shan Shan Yu
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Delay Time ◽  
Vehicular Traffic ◽  
Signal Design ◽  
Transit Signal Priority ◽  
Transit System ◽  
Travel Delay ◽  
The Impact ◽  
Wave Control

A good traffic signal design is one of the key solutions to many transportation problems. A two-way green wave control strategy for transit signal priority is reviewed and evaluated in this paper. Considering the traffic tidal phenomenon along the arterial roads during rush hours, a directional transit signal priority algorithm depend on the passenger flow has been developed for the coordination in signalized intersections. The algorithm provides signal timing plans for each intersection and the optimal bus speed along each section based on two-way bandwidth maximization. The strategy was designed to provide sectional control on transits, using electric signs and existing traffic control devices. In this paper, the strategys efficiency was evaluated using VISSIM micro-simulation along an arterial road which contains five intersections and serves more than ten bus lines. Actual data was used in the simulation. The simulation results show that the presented algorithm can effectively improve the operation efficiency of the transit system. This green wave control strategy reduced the number of stops by 34 % to 47 % and travel delay time by 27 % to 30% of the transit, while restricting the impact on vehicular traffic to the minimum. Moreover, the number of stops and travel delay time of vehicular traffic actually got a slight decrease. The algorithm shows promising results, and with minor upgrades, it can be applied to any type of intersection.

A Study of an Adaptive Two-Phrase Signal Control Strategy for Resolving Conflicting Transit Signal Priority Calls

2014 ◽  
Vol 505-506 ◽  
pp. 1028-1036
Author(s):  
Liu Yi Gao ◽  
Xiao Jian Hu ◽  
Wei Wang ◽  
Xue Dong Hua
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Simulation Software ◽  
Signal Control ◽  
Transit Signal Priority ◽  
Adaptive Signal Control ◽  
Vehicle Systems ◽  
Micro Simulation ◽  
Travel Delay ◽  
Adaptive Signal

This paper presents the development and evaluation of an adaptive two-phrase signal control strategy to resolve conflicting Transit Signal Priority (TSP) requests. The strategy was designed to provide adaptive transit signal priority control, using vehicle systems and existing traffic control devices. In this paper, the strategys efficiency was tested using a micro-simulation software VISSIM and build one arterial road contains five intersections and serves more than twenty conflicting bus lines. The VAP module was used to control TSP of conflicting requests. In the simulation, actual data was used. Finally, control efficiency about adaptive signal control strategy is discussed. The results show that the presented strategy can improve the operation efficiency of bus corporations. This signal control strategy reduced the travel delay time by 33 % to 55% of transit, while has little impact on private traffic. The strategy shows promising results. In addition, with minor upgrades, it can be applied to any type of intersection.

The impact of dwell time variability on transit signal priority performance

2014 ◽  
Vol 41 (2) ◽  
pp. 154-163 ◽  
Author(s):  
Mohammad S. Ghanim ◽  
Francois Dion ◽  
Ghassan Abu-Lebdeh
Keyword(s):  
Control Strategy ◽  
Dwell Time ◽  
Signalized Intersections ◽  
Time Variability ◽  
Transit Signal Priority ◽  
Operational Control ◽  
Priority Systems ◽  
Bus Delay ◽  
Transit Agencies ◽  
The Impact

Transit signal priority (TSP) is an operational control strategy that provides preferential treatments for transit vehicles at signalized intersections. Many transit agencies are currently considering the implementation of priority systems providing buses with preferential treatments at signalized intersections. While studies have demonstrated potential bus delay reductions, none has attempted to identify the problems posed by variable dwell times at bus stops. This study identifies the impacts of variable dwell times on the efficiency of transit signal priority systems. Results also show that, in general, variable dwell times negatively affect the TSP performance. However, and contrary to expectations, a number of scenarios with variable dwell times resulted in lower average bus delays than scenarios with fixed dwell times. These results are attributed to changes in progression and bus arrival patterns under variable dwell times resulting in an increasing number of buses arriving close enough to benefit from preferential treatments.

Research on Calculating the Parameters of Signal Timing for TSP Based on Enumeration Method

2013 ◽  
Vol 756-759 ◽  
pp. 3094-3098
Author(s):  
Tian Hong Gu ◽  
Hui Jian Cao
Keyword(s):  
Communication Technology ◽  
Delay Time ◽  
Traffic Signal Control ◽  
Signal Timing ◽  
Transit Signal Priority ◽  
Average Delay ◽  
Real Time Traffic ◽  
Simulation Results ◽  
The Impact

It is of importance to calculate the parameters of signal timing for TSP (Transit Signal Priority). However, most studies computing the delay are provided based on formula of triangle area. With communication technology developing precisely calculating the delay time of buses can be achieved. The kernel algorithm of TSP still has room for improvement. In this paper, the algorithmic flow of the most of functions is presented based on Enumeration Method.Meanwhile the study uses the VISSIM simulation model to evaluate the impact of a number of alternative priority strategies on both the prioritized buses and general traffic. The priority logic that is considered in the study provides signal timing parameters within a real-time traffic signal control environment. A case study was conducted to validate the model results. Simulation results shows that this method effectively reduces average delay time of the travelers.

Research on the Improved Algorithm of Transit Signal Priority Based on Bi-Objective Optimization Model

2013 ◽  
Vol 380-384 ◽  
pp. 1641-1644
Author(s):  
Tian Hong Gu ◽  
Hui Jian Cao
Keyword(s):  
Control Systems ◽  
Traffic Control ◽  
Optimization Model ◽  
Signal Timing ◽  
Transit Signal Priority ◽  
Constraint Condition ◽  
Arterial Road ◽  
Traffic Signal Timing ◽  
The Impact ◽  
Urban Arterial

Optimization of adaptive traffic signal timing is one of the most complex problems in traffic control systems. In order to obtain control parameters of transit signal priority of the urban roads, a bi-objective optimization model for signal timing is established. The delay and stop times as the goal of optimization are calculated respectively. And the corresponding constraint condition is built. The method can optimize green splits and offset at the urban arterial road. A VISSIM simulation was developed to evaluate the performance of the proposed bi-objective optimization model. The results show that the optimizer can produce TSP timing plans that benefit the transit vehicles while minimizing the impact of TSP on the general vehicles.

Existing Problems of Transit Signal Priority on Streetcar Routes

2020 ◽  
Vol 2674 (10) ◽  
pp. 861-873
Author(s):  
Ivan Kwong ◽  
Mehdi Nourinejad ◽  
Amer Shalaby
Keyword(s):  
Statistical Analysis ◽  
Control Strategy ◽  
Traffic Control ◽  
Arrival Time ◽  
Transit Signal Priority ◽  
Activation Time ◽  
Existing Problems ◽  
Passenger Travel ◽  
Transit Routes ◽  
The City

Transit signal priority (TSP) is a traffic control strategy that gives priority to transit vehicles by adjusting intersection signals in real time. The technology is implemented in many major cities and has proved to benefit transit routes in reducing the overall passenger travel time. Unfortunately, there are several problems with TSP that are commonly ignored. These problems are predominantly operational, such as misjudgment of the arrival time at the intersection and insensitivity to the TSP activation time. It is worsened with streetcars, which have shorter headways and thus are more prone to bunching delays. In this paper, five delay problems that streetcars experience are identified. Data are collected from a TSP-equipped intersection in the City of Toronto to provide a statistical analysis of the issues. It was found that 25.8% of times, TSP is inadequate at prioritizing public transit. From the problems raised, the most frequent one is the late arrival of a streetcar during a green interval, representing 72.5% of TSP issue cases. It was also found that TSP has a bias toward different failure cases, and favors early arrivals to the intersection. Several remedies for the defined issues are recommended. The suggestions include implementing green truncations, avoiding late TSP activation in each cycle, and introducing a prediction-based TSP system.

scholarly journals Onchocerciasis control in Ghana (1974–2016)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nana-Kwadwo Biritwum ◽  
Dziedzom K. de Souza ◽  
Odame Asiedu ◽  
Benjamin Marfo ◽  
Uche Veronica Amazigo ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Vector Control ◽  
Control Strategy ◽  
Financial Support ◽  
Control Programme ◽  
Ivermectin Treatment ◽  
Mobile Community ◽  
The Mean ◽  
The Impact ◽  
Onchocerciasis Control

Abstract Background The control of onchocerciasis in Ghana started in 1974 under the auspices of the Onchocerciasis Control Programme (OCP). Between 1974 and 2002, a combination of approaches including vector control, mobile community ivermectin treatment, and community-directed treatment with ivermectin (CDTI) were employed. From 1997, CDTI became the main control strategy employed by the Ghana OCP (GOCP). This review was undertaken to assess the impact of the control interventions on onchocerciasis in Ghana between 1974 and 2016, since which time the focus has changed from control to elimination. Methods In this paper, we review programme data from 1974 to 2016 to assess the impact of control activities on prevalence indicators of onchocerciasis. This review includes an evaluation of CDTI implementation, microfilaria (Mf) prevalence assessments and rapid epidemiological mapping of onchocerciasis results. Results This review indicates that the control of onchocerciasis in Ghana has been very successful, with a significant decrease in the prevalence of infection from 69.13% [95% confidence interval) CI 60.24–78.01] in 1975 to 0.72% (95% CI 0.19–1.26) in 2015. Similarly, the mean community Mf load decreased from 14.48 MF/skin snip in 1975 to 0.07 MF/skin snip (95% CI 0.00–0.19) in 2015. Between 1997 and 2016, the therapeutic coverage increased from 58.50 to 83.80%, with nearly 100 million ivermectin tablets distributed. Conclusions Despite the significant reduction in the prevalence of onchocerciasis in Ghana, there are still communities with MF prevalence above 1%. As the focus of the GOCP has changed from the control of onchocerciasis to its elimination, both guidance and financial support are required to ensure that the latter goal is met.

scholarly journals Quadrature Voltage Compensation in the Isolated Multi-Modular Converter

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 529
Author(s):  
Cristian Verdugo ◽  
Jose Ignacio Candela ◽  
Pedro Rodriguez
Keyword(s):  
Control Strategy ◽  
Phase Voltage ◽  
Multilevel Converters ◽  
Photovoltaic Panels ◽  
Circulating Current ◽  
Three Phase ◽  
Voltage Compensation ◽  
Wide Range ◽  
Modular Converter ◽  
The Impact

Series connections of modules in cascaded multilevel converters are prone to power imbalances due to voltage differences on their DC side. When modules are connected to direct current (DC) sources, such as photovoltaic panels, the capability of withstanding power imbalances is crucial for generating the maximum power. In order to provide a possible solution for this requirement, this paper proposes a control strategy called Quadrature Voltage Compensation, which allows a wide range of power imbalances. The proposed control strategy regulates the power by introducing a circulating current between the arms and a phase angle in the output voltage. The impact of the circulating current and its effect on the phase voltage are studied. To highlight the features of the proposed strategy, an analytical model based on vector superposition is also described, demonstrating the strong capability of tolerating power differences. Finally, to validate the effectiveness of the Quadrature Voltage Compensation, simulation and experimental results are presented for a three-phase isolated multi-modular converter.

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