Method of the left-turning bus priority at intersections based on a variable lane

To reduce the delay of left-turning buses and improve the traffic efficiency at signalized intersections,a novel variable bus approach lane(VBAL)control method based on bus pre-signals is proposed.This method combines the variable lane with the bus priority pre-signal,and realizes the left-turning bus priority without causing great impact on other vehicles.To validate the effectiveness of the method,the VBAL scheme was compared with the single left-turn lane scheme(SLTL)and the double left-turn lane scheme(DLTL).On this basis,the delay change calculation model of left-turning buses and through vehicles were established by the cumulative curve graphic method.The influence of vehicle proportion and green split on the model was studied through sensitivity analysis.The results show that VBAL can reduce the delay of left-turning bus and the increase of through vehicle delay to the greatest extent.Finally,the scheme was applied to a real-world intersection,and the results demonstrate the effectiveness and advantage of the VBAL scheme.

Multi-phase bus signal priority strategy at isolated intersections

To satisfy the multiple priority requests from buses that arrive at different phases within a small time window, a multi-phase bus signal priority （MPBSP） strategy is developed. The proximity principle is brought forward to settle the conflicts among multiple priority requests and arrange the optimal priority sequence. To avoid over saturation of the intersection, a conditional MPBSP algorithm that adopts early green and green extension strategies is developed to give priority to the bus with the highest priority level when green time that each phase runs makes its saturation degree not larger than 0. 95. Finally, the algorithm is tested in the VISSIM environment and compared with the normal signal timing algorithm. Sensitive analysis of the number of priority phases, bus demand, and volume to capacity ratios are conducted to quantify their impacts on the benefits of the MPBSP. Results show that the MPBSP strategy can effectively reduce bus delays, and with the increase in the number of priority phases, the reduction range of bus delays also increases.

Influence of bus stop with left-turn lines between two adjacent signalized intersections

Based on the symmetric two-lane Nagel–Schreckenberg（STNS） model, a three-lane cellular automaton model between two intersections containing a bus stop with left-turning buses is established in which model the occurrences of vehicle accidents are taken into account. The characteristics of traffic flows with different ratios of left-turn lines are discussed via the simulation experiments. The results indicate that the left-turn lines have more negative effects on capacity,accident rate as well as delay if the stop is located close to the intersections, where the negative effect in a near-side stop is more severe than that in a far-side one. The range of appropriate position for a bus stop without the bottleneck effect becomes more and more narrow with the increase of the ratio of left-turn bus lines. When the inflow is small, a short signal cycle and a reasonable offset are beneficial. When the inflow reaches or exceeds the capacity, a longer signal cycle is helpful. But if the stop position is inappropriate, the increase of cycle fails in reducing the negative effect of left-turning buses and the effectiveness of offset is weakened.

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 level was designed based on the isolated multi-phase structure principle consideration of the bus signal priority,and a new priority approach for the dynamic exclusive bus lane was proposed.Two types of priority strategies,green extension and red truncation,were proposed for current phase and next phase buses,respectively.The control parameters including minimum green time,green extension time,maximum green time and bus arrival time are calculated.The case studies for this paper were carried out using four consecutive intersections of Huaide Middle Road in Changzhou City.The signal control scheme was designed using the conventional,exclusive bus lane method,the dynamic exclusive bus lane without signal priority method,and the proposed approach,respectively.The authors used the VISSIM simulation platform to evaluate the efficiency of each approach.Results showed that the method of approach can significantly decrease delays caused by social and conventional buses and make up for the negative impact social buses have on the bus rapid transit(BRT)operation,which allows the method to complement the dynamic,exclusive bus lane design.

Control strategies and hardware-in-the-loop simulation for bus signal priority

It is considered as an important and effective means to give priority to the development of public transit which can improve the efficiency of transportation resources utilization and alleviate traffic jams. Public transit signal priority belongs to the "time priority" among the right-of-way priorities. After reviewing the existing bus priority signal control strategies and the advances in related technologies at home and abroad, this article analyzed the breakthrough direction of the bus signal priority design technologies suitable for China's conditions, and then proposed the hardware and software systems and the modules for the bus priority signal control system. Finally, the hardware-in-the-loop simulation (HILS) was introduced to evaluate bus priority signal control programs in order to optimize the control strategies.

Impacts of Coordinated Traffic Signal Control Strategies and Bus Priority

Delay in signalized intersections may constitute a significant part of bus journey times in urban environment. Providing priority for buses at traffic signals can be an effective measure to reduce this delay. Bus priority in Swedish urban traffic signal systems are normally coordinated with fixed time plan selection. Within this framework local traffic actuated signal timing adjustments are applied based on detector inputs aimed to reduce the number of vehicles in the dilemma zone. Active bus priority is also achieved with the aim to display green signal at the arrival of the bus to the stop line. Due to lack of knowledge of traffic performance impacts of these techniques a major research study was undertaken funded by the Swedish Road Administration. The aim was to evaluate the following control strategies using Stockholm as case study： （1） Fixed time coordination （FTC）; （2） Fixed time coordination with local signal timing adjustment （FTC-LTA）; （3） FTC-LTA with active bus priority （PRIBUSS）; （4） Self-optimizing control （SPOT） with active bus priority. The methodologies for the study included field data collection using mobile and stationary techniques, offiine signal timing calculations with TRANSYT, microscopic simulation modeling using the HUTSIM model. The study obtained the following results： （1） Local traffic adjustment with the manual FTC reduced total delay by 1%. （2） Signal timings determined using TRANSYT reduced the average intersection delay by 9% compared to manual signal settings. （3） Local traffic adjustment reduced total delay by a further 5%. （4） Bus travel time was reduced by 11% using PRIBUSS, and 28% using SPOT. （5） Travel time for all vehicles did not increase using PRIBUSS, and was reduced by 6.5% with SPOT. Results of comparing PRIBUSS and SPOT to FTC-LTA were shown to be statistically significant.

Optimal control system of the intermittent bus-only approach

To guarantee bus priority with a minimum impact on car traffic at intersections, an optimal control system of the intermittent bus-only approach （IBA） was proposed. The problems of the existing system are first solved through optimization： the judgment time of the IBA system was advanced to allow a bus to jump car queues if the bus was detected to arrive at the intersection, and the instant that the IBA lane became available to cars was controlled dynamically to increase the capacity of the IBA lane. The total car delay in one cycle was then analyzed quantitatively when implementing the optimal control system. The results show that in comparison with the existing system of the IBA, the car delay is greatly reduced and the probability of a car stopping twice is low after optimizing the IBA system.

A review of research on public transport priority based on CiteSpace

The prioritization of public transit as an essential means of promoting sustainable urban development has a significant role in improving the quality of public transportation services,reducing traffic congestion,and enhancing air quality.To improve the implementation of public transit prioritization policies,this study conducted a comprehensive review of relevant literature on public transit prioritization from two major citation databases(Web of Science and China National Knowledge Infrastructure)from 2003 to 2021.Utilizing the visualization analysis software CiteSpace,this study analyzed knowledge visualization from five aspects:research sources,research institutions,knowledge foundation,knowledge frontier,and research hotspots,and summarized the research history and implementation effectiveness of public transit prioritization policies.The study concludes that existing research has some deficiencies in terms of urban diversity,comprehensive evaluation system,holistic perspective,interdisciplinary collaboration,and consideration of economic and environmental impacts.Future research should focus on development directions such as intelligence,sustainability,interdisciplinary collaboration,and integration of multi-modal transportation.The findings of this study can provide valuable references for the implementation of public transportation prioritization policies and future research.