Bus Signal Priority Research Articles

Evaluating the performance of implementing regionally coordinating bus priority signals under different control schemes

Bus Rapid Transit (BRT) proves its effectiveness in alleviating traffic congestion, especially in urban areas. The implementation of Transit Signal Priority (TSP) for BRT has shown a significant reduction in delays. However, in densely populated urban areas, this priority can inadvertently cause additional delays for other modes of transportation. In this paper, we propose a control strategy for Regionally Coordinating Bus Priority Signals Control (RCBPSC) at urban intersections. The aim is not only to reduce bus delays but also to consider minimizing delays for pedestrians and other vehicles. To achieve this, we modeled two consecutive intersections along the Amman BRT. Essentially, we evaluated three different control scenarios in addition to the current base scenario. These scenarios include adaptive traffic signal control, RCBPSC with no signal timing optimization, and RCBPSC with signal optimization. Simulation results indicate that the adaptive traffic signal timing has the worst operational performance in terms of average delay and Level of Service (LOS) compared to the base scenario. Additionally, the results show that BRT delays significantly decrease at both intersections when we implement RCBPSC scenarios. When implementing RCBPSC with optimization scenarios, the results show an average reduction of more than 60% in intersection delay, a decrease in emissions of more than 50%, and an improved LOS for system users compared to the base scenario. The findings of this work can help agencies improve the current operational condition of BRT when implementing RCBPSC.

Adaptive Sustainable Mobility Solutions by Using Vehicle-Integrated Photovoltaic in Kigali City

In a fast-paced urbanized culture, sustainable transportation remains a significant challenge. Quick and smooth mobility of people and goods with the possibility of regulating traffic congestion and preventing climate change is essential for every public transportation user. Urban population in developing nations like Rwanda is expected to double by the year 2050, and balancing the supply and demand of the urban transport system will be a significant issue. Information technology enables elements within the transportation system, including vehicles, roads, traffic lights, and message signs, to become intelligent by embedding them with sensors, processors, algorithms, and actuators, thus empowering them to communicate through various technologies. These technologies improve transportation system performance by reducing congestion, increasing safety and traveler convenience, and protecting the climate against some greenhouse gases. Different mobility solutions are stated in this document. The use of electric vehicles, Passenger Information Systems, Car-sharing and ride-sharing services, electronic payment, Bus Signal Priority, and Vehicle-Integrated Photovoltaics. Using photovoltaics in Rwanda is adequate because of the electricity problem. This is the best solution for fighting against climate change due to fuel from motorized traffic.

A Bus Signal Priority Control Method Based on Deep Reinforcement Learning

To investigate the issue of multi-entry bus priority at intersections, an intelligent priority control method based on deep reinforcement learning was constructed in the bus network environment. Firstly, a dimension reduction method for the state vector based on the key lane was proposed, which contains characteristic parameters such as the bus states, the flow states, and the signal timing. Secondly, a control action method that can adjust phase sequence and phase green time at the same time was proposed under the constraints of maximum green and minimum green. Furthermore, a reward function, which can be uniformly converted into the number of standard cars, was established focusing on the indexes such as the busload and maximum waiting time. Finally, through building an experimental environment based on SUMO simulation, a real-time bus signal priority control method based on deep reinforcement learning was constructed. The results show that the algorithm can effectively reduce the waiting time of buses without affecting overall traffic efficiency. The findings can provide a theoretical basis for the signal control method considering bus priority and improve the operation efficiency of public transport.

Coordinated Control Method of Bus Signal Priority and Speed Adjustment Based on Stop-Skipping

There is an inherent coupling relationship between the time when buses arrive at the station and the time when they arrive the intersection, and it is essential to study the relationship as a whole to maximize the benefits of company operations and passenger services. In this study, a coordinated control method of signal priority and speed regulation in the stop-skipping mode at peak hours is proposed. First, the decision result of stop-skipping is obtained based on the historical passenger flow data. On this basis, the signal-priority decision is made for each vehicle in combination with the signal period and the arrival time of the intersection, and coordinated control is carried out in combination with the speed adjustment. The result of the genetic algorithm shows that cooperative control and prevention can minimize the passenger delay time and enterprise operation cost. The conclusions obtained in this research lay a theoretical foundation for company operation and signal-priority triggering mechanism.

Optimization model for bus priority control considering carbon emissions under non-bus lane conditions

Green extension and red truncation strategies were examined to study the influence of bus priority control strategies on traffic carbon emissions under non-bus lane conditions. Considering the main influencing factors, such as the delay and parking times, a bus speed probability density function based on the fluctuation characteristics of the vehicle speed in the intersection control area was introduced. A bus priority control optimization model was developed for non-bus lane conditions to optimize the carbon emission reductions of buses and social vehicles with different fuel types under different working conditions, and the Frank–Wolfe algorithm was used to solve the model. According to the model, when bus signal priority control was adopted under a green extension strategy, the carbon emission reductions were optimal (24.38%) when the green extension was 6 s. Under a red truncation strategy, the carbon emission reductions were optimal (26.01%) when the red truncation was 5 s. These results suggest ways in which carbon emissions in the intersection control area can be reduced to achieve the optimal overall traffic benefit for the intersection.

An Online Optimal Bus Signal Priority Strategy to Equalise Headway in Real-Time

Bus bunching is a severe problem that affects the service levels of public transport systems. Most of the previous studies in the field of Bus Signal Priority (BSP) and Transit Signal Priority (TSP) focus on reducing a bus delay at signalised intersections and ignore the importance of balancing the bus headways. However, since general BSP methods allocate uneven priorities for individual buses, the headways of bus sequences are prioritised or delayed randomly, increasing the likelihood of bus bunching. To address this problem and to improve the reliability of bus services, we propose an online optimisation model to determine the signal duration and splits for each traffic intersection and each signal cycle for bus priority. The proposed model is able to induce the signal timing back to a baseline when the BSP request frequency is low. Using the proposed model, a statistically significant reduction of 10.0% was achieved for bus headway deviation and 6.4% for passenger waiting times. The simulation-based evaluation results also indicate that the proposed model does not affect the efficiency of bus services and other vehicles significantly.

Regional Coordinated Bus Priority Signal Control Considering Pedestrian and Vehicle Delays at Urban Intersections

Bus priority signal control can reduce bus delay at intersections and improve bus operation efficiency. The existing research focus mainly on bus priority control methods at isolated intersections, as well as urban arterial corridors. Rarely existing works consider a network-level bus priority control. Treating regional-wide intersections can be challenging, given that more traffic directions and large multi-modal traffic volume should be considered. The conventional transit signal priority (TSP) research focus on the delay of buses and social vehicles and neglect the delay of pedestrians. To fill these gaps, this paper proposes a regional coordinated bus priority signal control (RCBPSC) method, which is a network-level bus priority control method considering pedestrian and passenger delays. This method is divided into two stages. The first stage is the regional coordinated signal control to obtain the basic signal timing schemes. The second stage is the bus priority signal control. At this stage, the timing schemes at each intersection will be adjusted according to the bus arrival time and the delays. In order to verify the effectiveness of this method, we choose four intersections in Chengdu to study. The results show that the total delay of the proposed method at the first stage (control case 1) can be reduced by 602s (2.3%) and 606s (3.7%) comparing with the conventional timing method in the peak and non-peak period. At the second stage, the proposed method can reduce more pedestrian delay than the conventional TSP method in both <xref ref-type="other" rid="other1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">scenario 1</xref> and <xref ref-type="other" rid="other2" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">scenario 2</xref> .

A Review on Bus Signal Priority Systems

A Review on Bus Signal Priority Systems

Analysis of Bus Signal Priority Effect by BRT Stop Types: Focusing on Hannuri-daero, Sejong

Analysis of Bus Signal Priority Effect by BRT Stop Types: Focusing on Hannuri-daero, Sejong

A Bus Signal Priority Model at Oversaturated Intersection under Stochastic Demand

This paper focuses on the optimization of bus signal priority with the consideration of the stochastic traffic demand. Based on a situation of the variability of traffic composition, the phase clearance reliability (PCR) value of each phase and traffic composition ratio is introduced to reflect the traffic condition at intersection. Then, a bus signal priority optimization model is proposed with the purpose of the maximum of the total vehicular departure as the optimization goal. In order to obtain the optimal solution, an improved algorithm is designed by introducing the PCR value search strategy. Finally, two cases’ study is exhibited to demonstrate the reasonability of the model, theory, and algorithm. The result shows that the model can not only clear the queue under the condition of continuous dynamic traffic flow but also reduce the vehicle queuing and passenger delay.

An integrated intersection design for promoting bus and car traffic

Signal priority and exclusive bus lanes are common measures used to promote bus travel at signalized intersections. However, these bus priority measures create significant damage to the car traffic especially at intersections with heavy bus and car traffic. For this reason, bus priority is not welcome at busy intersections. We examine a novel intersection approach design that can solve the above dilemma. The design integrates a bus lane, bus signal priority, and a midblock pre-signal for sorting different car traffic streams in tandem in the approach. Car capacity gains from the use of pre-signal can potentially recover the car capacity lost to bus lane and signal priority schemes. This paper first presents how the pre-signal and main signal can be timed to realize bus signal priority, and where the pre-signal should be placed. Models are then formulated for estimating the expected bus delay and car capacity under the integrated design. They are compared against three alternative designs, including a conventional intersection design without bus priority or pre-signal. Numerical results unveil that the integrated design produces not only significant bus delay savings, but also higher car capacities in most instances. Even greater car capacity gains are observed with higher bus frequencies. Moreover, the benefits are fairly robust when real-world operating features, such as bus arrival time prediction error, are considered. Thus, the integrated design can potentially promote both bus and car traffic at congested intersections.

Bus Rapid Transit System Introduction in Johor Bahru: A Simulation-Based Assessment

Bus rapid transit (BRT) is one of the strategies to promote improvements in urban mobility. In this study, BRT scenarios, which integrate exclusive bus lanes and bus priority signal control in mixed traffic scenarios, were modelled using a VISSIM microsimulation. Three scenarios of BRT were modelled to represent 16:84, 38:62 and 54:46 modal splits between public transport and private vehicles. It was found that Scenario 4 (the 54:46 scenario) offers better benefits in terms of delay time saving and economic benefits. In general, it was found that the BRT system enhances the functioning of the transport system and provides people with faster and better mobility facilities, resulting in attractive social and economic benefits, especially on a higher modal split of public transport. It is regarded as one strategy to alleviate traffic congestion and reduce dependency on private vehicles. The finding of this study provides an insight on the effective concept of the BRT system, which may promote the dissemination of an urban mobility solution in the city. The results can help policymakers and local authorities in the management of a transport network in order to ensure reliable and sustainable transport.

An Overlapping Phase Approach to Optimize Bus Signal Priority Control under Two-Way Signal Coordination on Urban Arterials

With the consideration of the uneven traffic volume distribution at intersections on urban arterials, this paper aims to minimize the overall passenger delay (buses and private vehicles) at intersections and identify the applicable conditions of the proposed method with field data. The overlapping phase-based signal control logic and the bus priority control algorithm under two-way signal coordination on arterial roads are proposed. The vehicular capacities and occupancies for buses and passenger cars are considered in the evaluation of the method performance. A field test was carried out at two major intersections on an arterial road in Hefei, China. With the test data, the proposed method is examined and the possible influencing factors are analyzed for identifying the corresponding applicable conditions. The analysis result shows that the application of the overlapping phase helps to provide a relatively flexible signal control for the varying traffic demands at intersections. Compared to the conventional phase, it isof more practical significance to consider overlapping phase and apply bussignal priority control under two-way signal coordination according to the condition of uneven traffic volumedistribution at intersections on urban arterials. The proposed method can effectively decrease the total passenger delay at the intersections on urban arterials under certain applicable conditions. The possible factors influencing the method applicability are identified as well. It is verified that bus signal priority control under the two-way signal coordination, based on overlapping phases, is more conducive to improving traffic efficiency on urban arterials. Regarding the influencing factors and the applicability of the proposed method, the results show that not all situations are conducive to decreasing passenger delay at intersections. The proposed method should be applied under certain applicable conditions and principles in order to efficiently and effectively improve the traffic efficiency on arterial roads.

An analytical approach to real-time bus signal priority system for isolated intersections

Bus signal priority (BSP) is an active traffic management measure to reduce bus travel delay at signalized intersections and to improve the bus service reliability. In this paper, we present a real-time BSP system with a primary focus on its practical implementation. We tackle two inter-related issues of existing priority systems, namely, real-time computation and solution optimality, using an analytical approach. The core of the proposed priority system involves two signal controller actions – red truncation (RT) and green extension (GE), which determine the priority timings based on the objective of minimizing total person delay incurring at the subject intersection. We demonstrate the analytical approach by deriving closed-form expressions for optimal RT and GE for a two-phase signal using cumulative count curves. The inputs required for these priority models are based on average traffic and bus conditions limited to the current signal cycle alone. Solutions for the RT and GE models indicate that three dimensionless variables – ratio of bus-arrival time to traffic queuing time, ratio of bus passenger occupancy to other vehicles’ average passenger occupancy, and ratio of traffic demand to saturation flow ratio – govern the priority decisions. Simulation results showed significant delay reduction for buses (≈22%) with a negligible impact on other traffic users during low to medium traffic conditions and high bus frequencies (3 min headway).

Dynamic Thresholds Identification for Green Extension and Red Truncation Strategies for Bus Priority

Among the different strategies adopted to improve the efficiency and reliability of the bus services, bus signal priority is a low cost and less infrastructure- demanding solution that has the potential to reduce bus travel times in urban arterials. This paper develops analytical models for finding the thresholds for Green Extension (GE) and Red Truncation (RT) for a four-phase signal system with buses on conflicting phases. The thresholds are developed based on reducing the total person delay after considering buses from the current cycle and unserved buses from the previous cycle for priority decisions. The proposed models aim for zero-delay service for the buses from the current cycle and reducing delay for the unserved buses from the previous cycle. The models reveal that at multi-phase signals, several bus priority alternatives are possible to reduce total person delay and agencies can choose alternatives based on their requirements and constraints. These models are evaluated in VISSIM microscopic simulation environment. The evaluation results indicate a 16.7 to 42.8% reduction in total person intersection delay due to the implemented bus priority.

Bus Priority Signal Control Considering Delays of Passengers and Pedestrians of Adjacent Intersections

In this paper, a bus priority signal control (BPSC) method based on delays of passengers and pedestrians at adjacent intersections, is proposed. The influences of BPSC on passenger and pedestrian delay at adjacent intersections under the condition of coordinated control of green waves are studied. The implementation of BPSC at intersections not only reduces the delay of bus passengers, social vehicle passengers and pedestrians, but also improves the traffic flow of priority buses and social vehicles at downstream intersections. This study takes the green phase extension as an example of the active BPSC strategy, and analyzes three cases of priority vehicles reaching downstream intersection. Firstly, passenger and pedestrian delays at adjacent intersections are calculated under different traffic situations. Secondly, models with the goal of maximizing the reduced total delays are established. Thirdly, three algorithms are used to solve the problem to obtain the optimal signal timing adjustment scheme at upstream intersections. Ultimately, the result shows that the BPSC can effectively reduce pedestrian delays at intersections, protect the rights and interests of pedestrians, reduce the delays of priority vehicles, and maximize the reduced total delay.

Simultaneous Optimization of Passive Transit Priority Signals and Lane Allocation

This paper presents an integrated optimization model for the concurrent design of passive bus priority signal settings and lane allocation including lane markings for general traffic and exclusive bus lanes at isolated intersections. Traditional passive transit signal priority (TSP) strategies considered both lane markings for general traffic and exclusive bus lane settings as exogenous inputs. However, in our method, two modes of transportation (passenger cars and buses) have been considered in a centralized framework while exclusive bus lane settings, lane markings, and the optimal passive transit priority signal settings can be optimized concurrently. Minimization of the weighted delay of buses and cars is adopted as the aim of the integrated optimization model. Based on traditional National Electrical Manufacturers Association (NEMA) phase constructure, a precedence graph was employed, by which the mathematical optimization model is formulated. A set of restrictions have been set up to verify efficiency and safety for the resulting optimal lane markings and signal settings. A simulated annealing (SA) algorithm is designed to resolve the mix-integer-nonlinear-programming (MINLP) problem. In order to demonstrate the efficacy of the method proposed, numerical examples have been provided. The results from sensitivity analysis show that the proposed method can generate sub-optimal solutions for the intersection of different combinations of car demand, bus demand, and left turn ratios.

Simultaneous Optimization of Passive Transit Priority Signals and Lane Allocation

This paper presents an integrated optimization model for the concurrent design of passive bus priority signal settings and lane allocation including lane markings for general traffic and exclusive bus lanes at isolated intersections. Traditional passive transit signal priority (TSP) strategies considered both lane markings for general traffic and exclusive bus lane settings as exogenous inputs. However, in our method, two modes of transportation (passenger cars and buses) have been considered in a centralized framework while exclusive bus lane settings, lane markings, and the optimal passive transit priority signal settings can be optimized concurrently. Minimization of the weighted delay of buses and cars is adopted as the aim of the integrated optimization model. Based on traditional National Electrical Manufacturers Association (NEMA) phase constructure, a precedence graph was employed, by which the mathematical optimization model is formulated. A set of restrictions have been set up to verify efficiency and safety for the resulting optimal lane markings and signal settings. A simulated annealing (SA) algorithm is designed to resolve the mix-integer-nonlinear-programming (MINLP) problem. In order to demonstrate the efficacy of the method proposed, numerical examples have been provided. The results from sensitivity analysis show that the proposed method can generate sub-optimal solutions for the intersection of different combinations of car demand, bus demand, and left turn ratios.

Evaluating the Environmental Impact of Bus Signal Priority at Intersections under Hybrid Energy Consumption Conditions

The acceleration of the motorization process creates severe environmental problems by affecting the energy consumption of urban traffic. As a major source of traffic pollution, vehicle exhaust deserves more attention when making traffic policy. Actually, the acceleration, deceleration, and idling conditions of vehicles cause more pollution than usual, which mainly happens at intersections of the road network. Besides, in the context of giving priority on public transport development, bus signal priority (BSP) at intersections becomes a quite prevalent measure to reduce average capita delay for travelers, while long-term practice also indicates that the unreasonable setting of bus lane further worsens the running conditions for other vehicles by occupying excessive traffic capacity, which highlights the indirect environmental effects of BSP. This paper provides a simulation-based method for evaluating the adaptability of BSP to find an optimum balance between efficient and environmental care. Specifically, the traffic volume, bus mixed rate of the intersection and energy types of vehicles consist of hybrid energy consumption conditions collectively. A VSP (vehicle specific power)-based exhaust emission models for both buses and other vehicles are employed to estimate the environmental cost of the entire intersection. Moreover, the overall efficiency of gasoline and electric vehicles is further evaluated to offer more implications for traffic control practice.

Bus Priority Control for Dynamic Exclusive Bus Lane

One problem with the existing dynamic exclusive bus lane strategies is that bus signal priority strategies with multi-phase priority request at intersections are not adequately considered. The principle of bus signal priority... | Find, read and cite all the research you need on Tech Science Press