Bus Delay Research Articles

Evaluation of Bus-Bicycle and Bus/Right-Turn Traffic Delays and Conflicts

This research evaluates conflicts and delays caused by interactions among buses, bicycles, and right-turning vehicles at a mixed traffic corridor in Portland, OR. The study site has a near-side bus stop and a right curbside lane designated for buses and right-turning vehicles. Next to the bus/right-turn lane is a bicycle lane with a bicycle box ahead of the bus stop (i.e., between the intersection and the bus stop). This research examines two concerns caused by these overlapping bus, bicycle, and automobile facilities; the first is the number of bus-bicycle conflicts (as a proxy for safety) and the second is bus delay. Video data was collected and analyzed to quantify conflicts, travel time, and delay. For every bus passing through the study site, the mixed traffic scenario that the bus incurs was categorized as one of 72 different combinations of bus, bicycle, and automobile interactions. Video count data was weighted according to seasonal, weekly, and hourly bicycle volume data to estimate the number of annual bus–bicycle conflicts. A regression analysis was performed to identify potential sources of delays. The results indicate that each bicycle crossing the intersection after the bus (within 60 ft of bus) contributes to bus delay. No statistically significant delay was found from the bicycles stopped in the bicycle box, bicycles stopped behind the bicycle box, bicycles that cross the intersection before the bus, or the presence of right-turning vehicles.

Coordinated Transit Signal Priority Model Considering Stochastic Bus Arrival Time

This paper presents an advanced transit signal priority (ATSP) control model that considers bus progression at downstream intersections when giving priority at upstream intersections and stochastic bus arrival times. The ATSP control model is applicable to arterials with bus lanes. At the center of the ATSP control model is a stochastic programming model formulated to find the optimum priority strategies at each intersection of interest, which minimize bus delays while having the least negative impact on general traffic. The uncertainty in bus arrivals is taken into account by considering stochastic bus dwell times. The ATSP control is implemented in a traffic micro-simulation environment and compared with conventional transit signal priority (CTSP) control. Extensive simulation experiments are conducted with different traffic congestion levels, bus headway levels, and dwell-time distributions. Results show that the ATSP control generates an additional reduction in bus delay of around 10% when compared to the CTSP control.

Optimisation of Bus Stop Layout Based on Time Distance Trajector

Under the background of arterial coordinated control, the location of a bus stop has a considerable influence on bus operations. In this study, the optimisation of the bus stop layout was investigated. Based on the time distance graph and green wave band, the distribution range of the travel trajectory of the bus flow on the road section was drawn. The travel trajectory distribution of two typical combinations of bus stop pairing layouts and intersections was analysed, and an ideal layout scheme with a staggered arrangement of a pairing layout and an intersection group was developed. For the reconstruction or new construction of a road, optimisation based on the local fine adjustment of the bus stop location, and the overall optimisation based on the ideal layout scheme were determined, respectively. The simulation results showed that the optimisation method based on the time distance trajectory had good manoeuvrability. The ideal layout scheme of bus stops could effectively reduce the bus delays and had a good optimisation effect. The deficiency was that the ideal layout scheme was restricted by the road condition and it had some limitations.

Assigning Bus Delay and Predicting Travel Times using Automated Vehicle Location Data

The Washington Metropolitan Area Transit Authority (WMATA) operates 1,250 buses on 168 different routes between 10,600 bus stops to support around 370,000 passengers each day. Utilizing sensors on vehicles and analyzing their location and movements throughout an hour, trip, or day can provide valuable information to a transit authority as well as to the users of a transit system. This amount of information can be overwhelming, but utilizing big data techniques can empower the data and the transit agency. First, this paper develops a methodology for assessing previous delays in the system by applying big data structure and statistical analysis to the data constantly collected by WMATA buses. This method of analysis also helps quantify the impact of potential transit system improvements. Second, the paper describes a model that uses the real-time data, that represents potential delays, to provide future passengers with more accurate arrival predictions despite delays. These analyses are powerful tools for agencies and planners to assess and improve transit service performance using big data analytics and real-time predictions.

Variable Signal Progression Bands for Transit Vehicles Under Dwell Time Uncertainty and Traffic Queues

Signal priority controls have long been viewed as one of the viable strategies to minimize bus delays at intersections so as to reduce the travel time variability or increase headway stability. Such control strategies, however, are often not effective for arterials serving heavy bus flows, because frequent signal priority calls will inevitably disrupt the arterial signal plan and incur excessive delays to general traffic. To overcome such deficiencies, this paper presents a bus-based signal progression model for arterials with heavy bus flows as in most major cities in Asia and Europe. The proposed model features its properties of accounting for the impacts of average bus dwell time, its variance, and the bus stop capacity. The impacts of various upstream traffic flow rates and signal plans on the available bus progression band have also been included in computing the optimal bus-progression offsets. Extensive simulation experiments have confirmed the effectiveness of the computed bus progression bands under various traffic congestion levels. The proposed bus-based pre-timed signal system can serve as a base plan for real-time operations of priority control for bus progression if the congestion level on the arterial or dwelling time variance as well as traffic queues have exceeded the operational capacity of the bus-based progression system.

Coordination Control for an Arterial Bus Based on the Ring-Barrier Phase

Coordination control is implemented on the main public transport system to reduce delay and improve the operation efficiency of buses on urban arterial roadways. First, the concept of a dual-loop phase is introduced and a new phase structure and sequences are proposed. Then, optimization models of the common signal cycle and effective green light time are built. Second, a genetic algorithm is used to optimize signal offset in coordination control according to the driving characteristics of a bus. To evaluate the effect of coordination control, a delay function is established to describe the control effect according to theory of triangle delay. Finally, the main arterial road is selected for a case study. The main parameters, such as common signal cycle, effective green light time, and offset, are optimized using Lingo and MATLAB. Results show that the bus delay value tends to decline after implementing the algorithm and the 50th iterative optimization result is 20.13% lower than that of the first iteration.

Performance of rc low encoding techniques for reducing coupling transitions

RC Network has delay propagation by wire and dynamic power dissipation. Basically it can perform two encoding techniques. They are Firstly it will reduce more dynamic power dissipation and delay propagation of wire simultaneously. Its simulation results of coupling activity and switching activity is more when the input is in Toggle state on 8-bit and for 32-bit data buses It increases. To reduce dynamic power is bus and total propagation delay the encoding techniques is Introduced which reduces coupling Coupling transitions, Dynamic power. Secondly it will also reduce more total power consumption when Width of Bus and Length of Bits Increases Its coupling activity is Reduced Gradually when the Data moves for one state to another State and switching activity is Reduced

Research on Priority Control Method of Conventional Public Traffic Signals

In this paper, for the bus on the main road of the single intersection, the main road of the bus is given priority. According to the strategy of early green light and green light extension, the bus time of the main bus is given more green time, and the bus is guaranteed while ensuring the efficiency of the intersection. Delays are minimized. At the multi-intersection transit priority, the analysis will focus on the possible delays caused by the motorcade at the intersection, and analyze the relationship between the delay and the non-heading delay in terms of the delay between the vehicle fleet and the intersection, and establish the per capita Delayed the smallest coordinated control model to achieve priority control of public transport signals. And the examples are introduced for verification. The results show that the green light extension and the green light early rise two different signal priority methods can effectively reduce the delay of the intersection bus.

Optimizing Transit Signal Priority Implementation along an Arterial

Transit signal priority (TSP) is a common method of providing priority to buses at signalized intersections. The implementation of TSP can affect travel time of cars traveling in the same, opposite, and cross directions. The bus delay savings and car travel-time impacts are not expected to increase linearly when considering multiple intersections along an arterial. This paper quantifies the influence of TSP on arterials with dedicated bus lanes considering an arterial-wide approach utilizing variational theory. Existing tools were modified to quantify the change in capacity along an arterial where TSP was implemented and it was shown that this effect was negligible. In addition, the bus delay savings and cross-street capacity losses were determined. Case studies provided insights into the influence of TSP among different network homogeneities and bus frequencies. Using these tools, an optimization framework was developed to determine where to implement TSP along an arterial to maximize the marginal benefits, or minimize marginal costs. In addition, a comparison of evaluating an arterial as a sum of isolated intersections as opposed to evaluating an arterial as a whole is presented. This analysis indicates the necessity of the arterial-based method in considering TSP impacts along corridors.

Bus Capacity Estimation using Stochastic Queuing Models for Isolated Bus Stops in China

When serving passengers at a bus stop, a dwelling bus may cause a bottleneck that constrains traffic flow near the bus stop. A major element in bus system capacity is bus stop capacity (veh/h). Therefore, this study proposes a method estimating the capacity of bus stops isolated from the influences of traffic signals and other bus stops. Data collected for the seven most common bus stop configurations in China were used to validate the proposed model. The results indicated that the arrival process obeys a Poisson distribution and the service times fit a lognormal distribution. Stochastic queuing models for both single-berth and multi-berth stops were developed to estimate bus stop capacity and bus delay time. To enable comparison, the Highway Capacity Manual (HCM) model for bus stop capacity estimation was also used. The results showed that the proposed method was more accurate and reliable, with a mean absolute percentage error (MAPE) of 8.44% compared with a MAPE of 17.42% from the HCM method. In addition, the proposed method reduced root mean squared error (RMSE) by 58.8%, mean absolute error (MAE) by 57.9%, and variance of absolute percentage error (VAPE) by 52.6% compared with the values from the HCM model. Sensitivity analyses were also conducted to investigate the effects of bus arrival rate, bus service time, and the number of bus berths on the capacity of bus stops. The results indicated that the proposed method can be used as a guide for designing bus stop facilities under specified conditions.

Multi-task parallel collaborative design based on SoC multi-core architecture

The high efficiency is demanded in aerospace field. In the design of the control system, adopting single processor can hardly meet the demand of efficiency required. However processor array's hardware size and off-chip bus delay cannot be ignored. In order to solve the above mentioned problems, this paper is intended to study multi-task collaborative parallel design based on multi-core SOC (system on chip). Firstly, multi-core architecture based on SOC is achieved, which includes constructing two MicroBlaze cores, two ARM (advanced RISC machines) cores and designing inter-core communication, as well as designing external data collection and hardware acceleration unit based on FPGA (field programmable gate array). Secondly, collaborative parallel design in missile control system is studied. Finally, a verification platform is developed. By comparing with single core processor, it is proved that the approaches proposed have advantages over enhancing the efficiency.

Multi-task parallel collaborative design based on SoC multi-core architecture

The high efficiency is demanded in aerospace field. In the design of the control system, adopting single processor can hardly meet the demand of efficiency required. However processor array's hardware size and off-chip bus delay cannot be ignored. In order to solve the above mentioned problems, this paper is intended to study multi-task collaborative parallel design based on multi-core SOC (system on chip). Firstly, multi-core architecture based on SOC is achieved, which includes constructing two MicroBlaze cores, two ARM (advanced RISC machines) cores and designing inter-core communication, as well as designing external data collection and hardware acceleration unit based on FPGA (field programmable gate array). Secondly, collaborative parallel design in missile control system is studied. Finally, a verification platform is developed. By comparing with single core processor, it is proved that the approaches proposed have advantages over enhancing the efficiency.

OPTIMIZING PHASE COMPRESSION FOR TRANSIT SIGNAL PRIORITY AT ISOLATED INTERSECTIONS

Transit signal priority (TSP) is a promising low-cost strategy that gives preferential treatments for the buses to go through intersections with minimum delay time. In this paper, a new TSP control model was presented for isolated intersections to minimize bus delay and to reduce the impact of TSP on other vehicles by optimizing signal control phase selection and compression. This paper starts with the phase selection and compression strategies to provide treatments to bus priority requests. Then, two new features on phase selection and compression aspects are applied to TSP, i.e. the time that a bus priority request needs is provided by the phase(s) with the lowest traffic volume, and multi-phases can be selected to serve a bus request. Field data are collected from a major traffic corridor in Changzhou (China) and applied for VISSIM simulation. The proposed TSP control model as well as the fixed-time control and the conventional TSP control models are tested and compared under different traffic demands, headways and maximum saturation degrees. The comparative results showed that the proposed model outperformed the conventional TSP control model in terms of reducing bus delay, minimizing the impact on other vehicles and reducing the stop rate for buses. This paper reveals that, the proposed TSP strategy can significantly optimize the phase compression process and improve transit efficiency.

Analytical Approach to Estimate Delay Reduction Associated with Bus Priority Measures

Bus delay reduction is an essential input to the objective evaluation of the performance of Public Transport Priority (PTP) measures. Functions for estimating bus delay reduction associated with various types of PTP measures can be used to optimise priority and signal control, or used as a planning tool when more expensive simulation is not available. However, existing delay functions for evaluating PTP measures, such as Dedicated Bus Lanes (DBLs) or Transit Signal Priority (TSP), tend to ignore delay associated with bus acceleration. Moreover, there is no study dedicated to developing bus delay functions to evaluate the performance of Queue Jump Lanes (QJLs) or QJLs combined with TSP. This paper proposes delay functions to analytically estimate bus delay effects for a range of PTP measures, including DBLs, QJLs, TSP, TSP combined with QJLs, and TSP combined with DBLs. Kinematic Wave Theory (KWT) is used to estimate queuing delays at traffic signals. Delay associated with bus acceleration is also analytically approximated. The proposed bus delay functions are validated using traffic micro-simulation, which indicates that the proposed functions accurately estimate bus delay effects of the considered PTP measures with small errors.

Estimating the Impacts of Bus Stops and Transit Signal Priority on Intersection Operations: Queuing and Variational Theory Approach

Transit signal priority (TSP) can be used to improve bus operations at signalized intersections, often to the detriment of general car traffic. However, the impacts of TSP treatments applied to intersections with nearby bus stop locations are currently unknown. This paper quantifies changes in intersection capacity, car delay, and bus delay when priority is provided to buses that dwell at near- or farside bus stop locations through green extension or red truncation. Variational and kinematic wave theories are used to estimate car capacity and bus delay for oversaturated traffic conditions; queuing theory is used to estimate car and bus delays for undersaturated conditions. Numerical analyses are conducted to explore the impacts on various bus stop locations and bus dwell time durations. These results illustrate clear trade-offs between reduced bus delays and increased car delays or reduced intersection capacities that can be quantified with the proposed method. The results also reveal that the effects of TSP vary dramatically with bus dwell times for a given bus stop location. The proposed method and associated results can be used to implement TSP strategies to meet the specific needs of local agencies.

Dissipating traffic congestion of emergency events through information guidance on mobile terminals

Abstract This paper presents emergency events in the urban road traffic system caused by bus delays buses and consequent congestion problems. It intends to dissipate the traffic congestion of passenger transport network. For the purpose of keeping the order of transit passengers and improving efficiency of transit service, it is important that transit passengers obtain the travel information when transit service is interrupted or delayed. There is also a need for the public transportation authority (PTA) to know how to use travel information to guide the passenger flow assignment and coordinate transport dissipation. This project builds emergency traffic congestion scenarios and adopt the Stated Preference questionnaire to acquire passenger’s travel demand information and distinguish sensitivity of demand factors. Then, it researches on the mechanism of sending group short messages (SMS) including partitioned methods, published time, contents and frequency to bus passengers using mobile terminals. This paper also presents published regulation of group short message sending on mobile terminals in emergency traffic events to PTA.

Does Combining Transit Signal Priority with Dedicated Bus Lanes or Queue Jump Lanes at Multiple Intersections Create Multiplier Effects?

An extensive body of literature deals with the design and operation of public transport (PT) priority measures. However, there is a need to understand whether providing transit signal priority with dedicated bus lanes (TSPwDBL) or transit signal priority with queue jump lanes (TSPwQJL) at multiple intersections creates a multiplier effect on PT benefits. If the benefit from providing priority together at multiple intersections is greater than the sum of benefits from providing priority separately at each of those individual intersections, a multiplier effect exists. This paper explores the effects of providing TSPwDBL or TSPwQJL at multiple intersections on bus delay savings and person delay savings. Simulation results reveal that providing TSPwDBL or TSPwQJL at multiple intersections may create a multiplier effect on one-directional bus delay savings, particularly when signal offsets provide bus progression for that direction. The multiplier effect may result in a 5% to 8% increase in bus delay savings for each additional intersection with TSPwDBL or TSPwQJL. A possible explanation is that TSPwDBL and TSPwQJL can reduce the variations in bus travel times and thus allow signal offsets—which account for bus progression—to perform even better. Furthermore, results show little evidence of the existence of a multiplier effect on person delay savings, particularly for TSPwQJL with offsets that favor person delay savings. A policy implication of these findings is that considerable PT benefits can be achieved by providing both time and space priority in combination on a corridorwide scale.

Level of Bus Performance Based On the Relationship Between Distance and Travel Time of Universiti Tun Hussein Onn Malaysia (UTHM) Bus Services

UTHM bus service is an important transport mode for most students at Universiti Tun Hussein Onn because it such primary public vehicle to support students movements around the campus, within and outside student apartments. This service is often associated with the quality of service in terms of time, stops and comforts. Therefore, this following study is focused on investigation on several UTHM bas routes which was based on bas operations such as distance and travel time/travel distance that would determine the level of service provided. Primary data were collected mainly to obtain information relate to speed, bas position, time movement/circulations of bus and time headway. These were obtained by installing GPS-Slute Gear i-trail along bus travels. In addition, additional data were collected by exploring previous studies regarding to the bus services such as Highway Capacity Manual (HCM 2010). The approach used was based on assessment of progress used to determine the level of quest service and such obstacle frequently occurs with results on bus delays, volume of unequal that can be overcome according to the assessments that have been provided.

Integrated optimization of bus priority operations in connected vehicle environment

SummaryMost previous works associated with transit signal priority merely focus on the optimization of signal timings, ignoring both bus speed and dwell time at bus stops. This paper presents a novel approach to optimize the holding time at bus stops, signal timings, and bus speed to provide priority to buses at isolated intersections. The objective of the proposed model is to minimize the weighted average vehicle delays of the intersection, which includes both bus delay and impact on nearby intersection traffic, ensuring that buses clear these intersections without being stopped by a red light. A set of formulations are developed to explicitly capture the interaction between bus speed, bus holding time, and transit priority signal timings. Experimental analysis is used to show that the proposed model has minimal negative impacts on general traffic and outperforms the no priority, signal priority only, and signal priority with holding control strategies (no bus speed adjustment) in terms of reducing average bus delays and stops. A sensitivity analysis further demonstrates the potential of the proposed approach to be applied to bus priority control systems in real‐time under different traffic demands, bus stop locations, and maximum speed limits. Copyright © 2016 John Wiley & Sons, Ltd.

Analytical and simulation approaches to understand combined effects of transit signal priority and road-space priority measures

Transit signal priority (TSP) may be combined with road-space priority (RSP) measures to increase its effectiveness. Previous studies have investigated the combination of TSP and RSP measures, such as TSP with dedicated bus lanes (DBLs) and TSP with queue jump lanes (QJLs). However, in these studies, combined effects are usually not compared with separate effects of each measure. In addition, there is no comprehensive study dedicated to understanding combined effects of TSP and RSP measures. It remains unclear whether combining TSP and RSP measures creates an additive effect where the combined effect of TSP and RSP measures is equal to the sum of their separate effects. The existence of such an additive effect would suggest considerable benefits from combining TSP and RSP measures. This paper explores combined effects of TSP and RSP measures, including TSP with DBLs and TSP with QJLs. Analytical results based on time-space diagrams indicate that at an intersection level, the combined effect on bus delay savings is smaller than the additive effect if there is no nearside bus stop and the traffic condition in the base case is under-saturated or near-saturated. With a near-side bus stop, the combined effect on bus delay savings at an intersection level can be better than the additive effect (or over-additive effect), depending on dwell time, distance from the bus stop to the stop line, traffic demand, and cycle length. In addition, analytical results suggest that at an arterial level, the combined effect on bus delay savings can be the over-additive effect with suitable signal offsets. These results are confirmed by a micro-simulation case study. Combined effects on arterial and side-street traffic delays are also discussed.