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Traffic safety studies need more than what the current micro-simulation models can provide, as they presume that all drivers exhibit safe behaviors. Therefore, existing micro-simulation models are inadequate to evaluate the safety impacts of managed motorway systems such as Variable Speed Limits. All microscopic traffic simulation packages include a core car-following model. This paper highlights the limitations of the existing car-following models to emulate driver behaviour for safety study purposes. It also compares the capabilities of the mainstream car-following models, modelling driver behaviour with precise parameters such as headways and time-to-collisions. The comparison evaluates the robustness of each car-following model for safety metric reproductions. A new car-following model, based on the personal space concept and fish school model is proposed to simulate more accurate traffic metrics. This new model is capable of reflecting changes in the headway distribution after imposing the speed limit from variable speed limit (VSL) systems. This model can also emulate different traffic states and can be easily calibrated. These research findings facilitate assessing and predicting intelligent transportation systems effects on motorways, using microscopic simulation.

In this paper, an approach for longitudinal vehicle control is proposed that integrates a Machine Learning model for the speed prediction of the leading vehicle in order to improve the energy efficiency of the control in a city driving environment. The prediction is employed in an additional control mode that extends a conventional state-of-the-art speed and headway control. The approach aims to reduce the vehicle consumption through a more anticipatory driving style. The prediction model uses an encoder-decoder LSTM network with additional information from Vehicle-2-X communication and is trained through supervised learning with training data generated from simulation. A co-simulation environment comprising of an ego vehicle simulation and a microscopic traffic simulation is used for the generation of training data and the assessment of the control approach. The proposed control is compared to a benchmark Adaptive Cruise Control scheme for three battery electric vehicles with different powertrain specifications on multiple routes in a simulated city-driving environment of Darmstadt, Germany. The results show that the consumption of the vehicles can be reduced for all vehicles by 3–5 % while still maintaining similar mean speeds on different routes through the city.

Current sensing and control of self-driving vehicles based on full-view recognition is hard to keep a high-frequency with a fast moving vehicle, as increasingly complex computation is employed to cope with the variations of driving environment. This work, however, explores a light-weight sensing-planning framework for autonomous driving. Taking the advantage that a vehicle moves along a smooth path, we only locate several sampling lines in the view to scan the road, vehicles and environments continuously, which generates a fraction of full video data. We have applied semantic segmentation to the streaming road profiles without redundant data computing. In this paper, we plan vehicle path/motion based on this minimum data set that contains essential information for driving. Based on the lane, headway length, and vehicle motion detected from road/motion profiles, a path and speed of ego-vehicle as well as the interaction with surrounding vehicles are computed. This sensing-planning scheme based on spatially sparse yet temporally dense data can ensure a fast response to events, which yields smooth driving in busy traffic flow.

The increasing demand for railway capacity leads the railway industry to explore the next generation signal system such as virtual coupling. In this paper, a coupling model is established for two trains coming from different lines in the junction area to improve the coupling efficiency. Firstly, a nonlinear discrete model is developed by defining the objective function as the negative coupled time, and it satisfies the constraints in the classical optimal train control problem (e.g., running resistance, speed limit, and the train characteristics). Particularly, the effect of the switch on Movement Authority (MA) of trains and the safety protection constraints (e.g., headway) are emphasized. Then, the nonlinear constraints are linearized by Piecewise Affine (PWA) approximation and logical variables such that the optimization problem is turned into Mixed Integer Linear Programming (MILP) which be solved by the existing solver. Finally, some cases are conducted to illustrate the effectiveness of the proposed approach.

In the subway metro, the failure of the power supply system affects normal operation and brings many inconveniences to passengers. This paper proposes a train timetable rescheduling (TTR) model under power supply system failures. First of all, an optimization model that takes the deviation of rescheduled timetable and the cancellations of train services as the objectives is developed. In addition, train detention strategy and the strategy of dropping off trains in the storage line, as well as the constraint of increased headway in power supply failure area are considered in the model. Secondly, for the ILP problem can be solved by the existing solver (such as Cplex), the model is transformed into an integer programming model through linearization. Finally, some case studies are conducted based on the actual data of Beijing Fangshan Metro Line to demonstrate the effectiveness of the proposed approach. The results show that the rescheduling model in this paper is feasible in actual metro lines.

This research proposed an analytical model of mixed flow consisting of Cooperative Adaptive Cruise Control (CACC) equipped vehicles and Human-driven Vehicles (HVs) in freeway merging areas. It quantifies the impact of CACC platoon on maximum throughput during the merge. The model describes the impedance of CACC platoon on lane change maneuvers together with its positive effect on maximum throughput due to shorter headway. To validate the effectiveness of the proposed model, a VISSIM based microscopic simulation evaluation is performed. The results confirm that the accuracy of the proposed model is over 80%. Sensitivity analysis is conducted in terms of various penetration rates of CACC equipped vehicles and v/c ratio levels. The proposed model demonstrates a consistent performance across all penetration rates and v/c ratio levels. The proposed model provides the foundation for future CACC-based traffic management strategies such as platooning strategy and dedicated lane management.

One of the vital processes in bus operation is timetable development. Timetable generation influences the whole operational structure of a bus network. Custom tailoring of commercially available software packages remains a challenge for small and medium bus organisations/companies operating in cities in India. This study aims at developing a tool for bus timetabling in a city that can be run on a widely available spreadsheet software. The objective is to produce timetables with maximum synchronizations to facilitate passenger transfers and avoid bus bunching along the network. The scheduling tool enables the users to input passenger data and analyse characteristics of each route in the network to study the operations of the bus service. The proposed solution algorithm coded as a Multi-start iterated local search algorithm was tested on different real-life examples. The total number of synchronizations was found to depend on the headway and the specified time limits mainly. From the test results, it can be inferred that the solver can be used to obtain efficient timetables with maximum synchronizations between routes.

Execution assessment of understudies is fundamental for check the plausibility of progress. Standard assessment improves the exhibition of the understudy as well as it helps in understanding where the understudy is deficient. It's anything but a ton of manual exertion to finish the assessment interaction as even one school may contain a great many students. Precisely predicting understudies future execution reliant upon their advancing insightful records is huge for effectively doing basic informative intercessions to ensure understudies' on-time and pleasing graduation. Disregarding the way that there is a rich composition on anticipat-ing understudy execution when handling issues or perusing for courses using data driven approaches, predicting understudy execution in completing degrees is extensively less inspected and faces new challenges: (1) Understudies contrast hugely with respect to establishments and picked courses; (2) Courses are not comparably illuminating for making exact assumptions; (3) Understudies' creating progression ought to be joined into the assumption. In this paper, we develop a novel AI procedure for expecting understudy execution in degree programs that can address these key challenges. Decisively following and expecting understudies future execution subject to their advancing insightful records to ensure understudies on-time and great graduation. Following and expecting understudy execution reliant upon degrees and here faces new challenges those are: Students shift gigantically in regards to establishments and picked courses, Courses are not comparably helpful for making careful figures, Students creating headway ought to be joined into the assumption. This paper proposed a computerized answer for the exhibition assessment of the understudies utilizing AI. A limit based division is utilized to finish the assessment strategy over MATLAB reenactment device. The exhibition of AI is assessed by exactness and mean square blunder

Bus bunching could seriously damage the stability of transit system. This resultant instability always causes a dissatisfying performance of transit system. Traditional bus bunching control methods (e.g., holding control strategy) add slack to schedules or adapt cruising speed. The control methods can alleviate bus bunching in theory, but it is difficult to apply to actual operation, especially in busy traffic. The short-turning strategy only deals with spatial concentration of demand in the existing literatures. We find that the short-turning strategy is also very effective in alleviating bus bunching. In this study, based on the passenger arrival rate of each stop and the spatial-temporal running time, a short-turning model with bunching penalty is developed, and the waiting time of passengers and the operation cost are also considered. Based on data from Beijing Transportation Information Center, we take the Yuntong 111 bus line of Beijing as an example. Compared with the currently used timetable, it is found that a 46.78% reduction in bus bunching is achieved by using the optimal timetable, and there is no increase in operating costs.

This article addresses the problem of dynamic event-triggered platooning control of automated vehicles over a vehicular ad-hoc network (VANET) subject to random vehicle-to-vehicle communication topologies. First, a novel dynamic event-triggered mechanism is developed to determine whether or not the sampled data packets of each vehicle should be released into the VANET for intervehicle cooperation. More specifically, the threshold parameter in the triggering condition is dynamically adjusted over time according to the vehicular data variations, the dynamic threshold updating laws, and the bandwidth occupancy indication. Second, a unified platooning control framework is established to account for various spacing policies, randomly switching communication topologies, unknown leader control input, and external disturbances. Then, a new scheduling and platooning control co-design approach is presented such that the controlled vehicular platoon can successfully track the leader vehicle under random communication topologies and different spacing policies, including constant spacing, constant time headway spacing, and variable time headway spacing, meanwhile maintaining efficient bandwidth-aware resource management. Finally, comparative studies are provided to substantiate the effectiveness and merits of the proposed co-design approach.

Based on a density gradient model proposed recently by Imran and Khan, a new heterogeneous traffic flow model considering time and lateral distance is proposed. The type and stability of the equilibrium solution of the model are discussed by using the differential equation theory, and the global distribution structure of the trajectory in the phase plane is analyzed. In addition, the density wave stability conditions and saddle-node bifurcation conditions of the model are studied, and the solitary wave solutions of the KdV equation in the metastable region are derived by using the reduced perturbation method. The numerical results show that the new model cannot only reproduce the spatiotemporal oscillation phenomenon when walking and stopping, but also describe the sudden change behavior of traffic near the critical point of saddle-node bifurcation. It is shown that the model can reproduce some complex traffic phenomena qualitatively.

With the advent of additive manufacturing and a flurry of new-generation, three-dimensional (3D) printers that hit the market in the early 2000s, biomedical innovators began envisioning the technology as a way to replace damaged or diseased tissue and organs with on-demand, printed parts [1] – [3] . The path from vision to reality was not quite as quick or easy as many anticipated, but research groups today are making headway to keep the technology moving toward its goal.

This study focuses on the issue of photograph recovery from a mixed database, with reality protection ensured both during the capacity and rebuilding processes. The focus of the article is on photograph headway security systems that involve relationships among defended features. Three plans are demonstrated and thought about by utilising each sign preparing and cryptographic strategies, in total with bitplane randomization, unpredictable projection, and randomised unary encoding. The results show that shielded image recovery can achieve a similar rebuilding look to conventional picture recovery schemes without disclosing the texture of the photograph's content material. This tutoring improves the domain of quiet contemplative reclamation and can discover fine art in secure online settings for pictures and chronicles.

The headway distribution study offers an insight into vehicle flow that can be useful to traffic studies and management in many respects; for example, with a better understanding of road traffic patterns and road user behavior, the researchers or engineers could make better estimate and predict traffic flow under certain road traffic conditions and thus improve traffic management. There is some research on headways in Saudi Arabia for free flow traffic on freeways, but few studies are for congested areas, such as weaving sections. This study has been done to statistically analyze headways in the weaving area of Makkah Road in Riyadh during peak time and find an appropriate distribution of headways. Headway data were acquired from the captured images of the traffic data recorded by video cameras. The following statistical analysis was based on that data. A special program was used to find a best-fit distribution for the headways, which was followed by a statistical verification process using the Kolmogorov-Smirnov (K-S) test.

As the infrastructure of urban development, China has been focusing on the construction of public transport and vigorously promoting the strategy of public transport priority. However, with the continuous development of economy, the high travel demand caused by the increasing of urban commuters result in the serious traffic jam and bus congestion. In this case, customized bus came into being. It can divert the conventional public transport, alleviate the congestion of conventional public transport and improve the comfort of passengers. In order to better understand the operation status of customized bus, we did the field research on the actual situation of Beijing public transport. Based on it, we do an empirical study of customized bus. Through the model to solve the most appropriate headway and number of departure, and finally we give the actual operation plan for the bus company. At the same time, the sensitivity analysis of important parameters is also carried out. Finally, the results show that our model can effectively alleviate the congestion of conventional public transport and realize the purpose of diverting conventional public transport into customized public transport.

Signal-free intersections for connected and autonomous vehicles (CAVs) is an emerging technology with significant efficiency and safety benefits. However, models for macroscopic performance evaluation and decision making have not been well developed. To address this, we consider a novel, analytical queuing model for CAV coordination at signal-free intersections. CAVs arrive at the intersection according to Poisson processes, and the service times are heterogeneous and sequencing-dependent. We use this model to quantitatively relate key operational parameters (vehicle speed/acceleration, inter-vehicle headway) to key performance metrics (throughput and delay). We apply the Foster-Lyapunov drift condition to obtain stability criteria, which leads to a lower bound for mean capacity and an upper bound for mean delay. We validate our model and results on a realistic microscopic simulation testbed. We also quantitatively estimate the performance improvement due to CAVs with respect to non-CAV intersections. Keywords: Connected and autonomous vehicles, signalfree intersections, piecewise-deterministic Markov processes, Lyapunov function.

Even though the safeguarding of automated driving functions is very present in automotive research, semiautomated and manually controlled systems will continue to be predominant in the next decade. Still, automation features such as driver assistance systems are becoming more prevalent and can operate more intuitively with the driver in a closed loop. Efficient interaction with the driver in partially automated systems can further improve road safety in the meantime. In this context, assessing the driver's perception of nearby traffic is crucial to making driver assistance safer and more collaborative. We propose a data-driven method to detect traffic-objects a driver is visually observing in the headway and side traffic using a multilabel neural-network as a classifier. This functionality is necessary to distinguish well controlled anticipatory driving from missing perception in partially automated driving. This could be an early reaction to decelerating vehicles ahead, even before a critical situation arises, or verification of the driver's perception of a cut-in. We validate the method using a data-driven ground truth from wearable eye trackers and automatically generated labels. Additional information comes from cameras installed in the vehicles to monitor the driver and traffic, as well as from measurement equipment that records CAN bus data. The proposed method achieves a Hamming accuracy of 69%, outperforming previous geometric models.

Fire security has become a significant worry with the headway of human development. Fire risks can be fatal and maligning for modern security systems. Nowadays, fire incidents are regular and challenging for firefighters to ensure people's lives. Because of this reason, this paper identified the necessity of firefighting robots for helping firefighters. The main goal is to identify the fire incidents and help the firefighter when firefighting. The robot will detect fire with a temperature sensor's help and go to the exact place, not making any collision because of the ultrasonic sensor. When it catches fire, it will send the feedback to the microcontroller and a camera sensor. It will send a real-time image to understand the situation appropriately. For making the proper surveillance robot, some commands and codes in Arduino and MATLAB are developed. They are using fuzzy logic as input so that after detecting any obstacle, the robot can easily take turns and move from there. By doing simulations and practical observations, the robotics system was successfully run. This paper gives a better safety measurement at the fire incidents time and helps the firefighter fight fire accidents.

The time headway distribution of vehicles plays a significant role in different traffic engineering applications. This paper investigated seven probability distributions that would mimic the distribution of the time headways on the Egyptian two-lane, two-way (TLTW) roads, namely (1) exponential, (2) lognormal, (3) gamma, (4) inverse Gaussian, (5) Pearson type III, (6) shifted exponential, and (7) Schuhl distributions. Two sites from two rural TLTW roads that connect Mansoura city to Damietta and Dikirnis cities are studied. One-hour videotaped data from each site were collected, for both directions. Besides, the Chi-square and the K–S goodness-of-fit (GOF) measures were used to assess which distribution fits the observed headway data better. Based on the observed data, about 75% of travel speed measurements are relatively closer in values (between 60 and 70 km/h) for both directions. Different bin widths (0.50, 1.0, and 2.0 s) along with the recommended bin size (3.0 s) by the Rice rule were used to model the observed headway frequency. The results confirmed that both of the GOF tests reveal the same results in terms of the acceptance and the rejection of the proposed distributions compared to the observed headways. In addition, both of the gamma and the shifted exponential distributions would be good representatives for modeling the time headways in the Dakahliya Governorate rural TLTW roads. Moreover, bin widths less than the recommended by the Rice rule did not affect the acceptance/rejection results of the proposed methods.

With rapid population growth and increasing demand for urban mobility, metropolitan areas such as Singapore, Tokyo, and Shanghai are increasingly dependent on public transport systems. Various strategies are proposed to improve the service quality and capacity of bus and subway systems. Express trains—i.e., trains that skip certain stations—are commonly used because they can travel at higher speeds, potentially reduce travel time, and serve more passengers. In this paper, we study cyclic express subway service (CESS), in which express trains provide routine transport service with cyclic (periodic) station-skip patterns that can be used in daily service. We propose an exact Mixed Integer Programming (MIP) model to optimize cyclic station-skip patterns for express trains operating in a single-track subway system. The objective is to reduce passengers’ total travel time—i.e., the sum of waiting time and riding time—while considering demand intensity and distribution and train headway, frequency, and capacity. We implement the model in a set of numerical experiments using real data from Singapore. To solve the optimization problem more efficiently, we also propose a heuristic to solve large-scale problems. We observe that the exact MIP model for CESS provides optimal cyclic express service patterns within a reasonable computational time, and the heuristic method can significantly reduce the computational time and provide a good solution. The case study demonstrates that passengers’ average travel time could be significantly reduced compared to local train service. We also discuss the potential transfer of passengers between express trains and evaluate its effects using numerical experiments.

This article studies a control method for multi-agent high-speed trains systems with dead-zone and input saturation. The problems of saturation and dead-zone were solved by subsidiary method. Then, we can design a potential function to guarantee the headway distances at stationary distances under the saturation and dead-zone. Then, we design Lyapunov function to ensure the stability and effectiveness. Finally, several simulation examples verify the effectiveness of our method.

The Cooperative Adaptive Cruise Control (CACC) system can reduce traffic flow and improve the safety of vehicles. The implementation of the CACC system requires the information over a vehicle to vehicle (V2V) communication and onboard sensors. In this paper, three control laws are designed based on the information available over the V2V communication channel. The proposed control laws are implemented and validated on a non-linear vehicle simulation tool CarSim and MATLAB/Simulink. The comparative performance of the proposed schemes is carried out for various headway time.

In this paper, we investigate the influence of train headways on passenger platform wait times using automated data from the London Underground metro system. For high frequency services, the literature suggests that passenger arrivals are random and that under perfectly random conditions with all other factors held constant, wait times are equivalent to half of the headway between trains. We test this hypothesis using large-scale smart card and vehicle location data, which enables the extraction of access times from total passenger journey times as well as the precise measurement of train headways. Using a semiparametric regression modelling framework, we generate non-linear estimates of the relationship between access times and headway while conditioning for other service supply and demand factors. Marginal platform wait times are then derived numerically via an exposure–response model framework which accounts for potential confounding between the walking and waiting components of access times, thus enabling quantification of the unbiased impact of headways on wait times. For three lines in central London, we observe that marginal wait times transition from greater than half of the headway to approximately one third of the headway as train frequencies decrease. The transition occurs in the range between 2-3 min headways, lower than earlier estimates in the literature. A series of numerical simulations illustrate the importance of waiting time sensitivity in the optimisation of public transport services. In comparison with the standard wait time assumption, our exercise reveals that the degree of density economies is milder than what the literature suggests, and this may neutralise some of the economic justifications of high public transport subsidies.

In this paper we analyze synthetic mobility traces generated for three-lane unidirectional motorway traffic to find that the locations of vehicles along a lane are better modeled by a hardcore point process instead of the widely-accepted Poisson point process (PPP). In order to capture the repulsion between successive vehicles while maintaining a level of analytical tractability, we make a simple extension to PPP: We model the inter-vehicle distance along a lane equal to the sum of a constant hardcore distance and an exponentially distributed random variable. We calculate the J-function and the Ripley's K-function for this hardcore point process. We fit its parameters to the available traces, and we illustrate that the higher the average speed along a lane, the more prominent the hardcore component becomes. In addition, we consider a transmitter-receiver link on the same lane, and we generate simple formulae for the moments of interference under reduced Palm measure for that lane, and without conditioning for other lanes. We illustrate that under Rayleigh fading a shifted-gamma approximation for the distribution of interference per lane provides a very good fit to the simulated outage probability using the synthetic traces, while the fit using the PPP is poor., to be published

We report the results of an experiment to evaluate the impact of transit signal priority (TSP) on headway adherence for a bus rapid transit (BRT) system in Provo / Orem, Utah. The bus requests TSP based on its unpublished schedule, but users perceive only a headway. Quantile regression models estimated on raw timepoint data from the BRT system reveal that TSP significantly improves headway adherence, after controlling for peak times, direction, and cumulative trip dwell time. We also find that requiring the bus to be 2 minutes late before requesting TSP improves headway adherence more than allowing all buses to request TSP.

In this work Rain Drop Optimization (RDO) Algorithm is projected to reduce power loss. Proceedings of Rain drop have been imitated to model the RDO algorithm. Natural action of rain drop is flowing downwardsform the peak and it may form small streams during the headway from the mountain or hill. As by gravitation principle raindrop flow as stream then as river form the peak of mountains or hill then it reach the sea as global optimum. Proposed Rain Drop Optimization (RDO) Algorithm evaluated in IEEE 30, bus test system. Power loss reduction, voltage deviation minimization, and voltage stability improvementhas been achieved

Problem. Currently, there exist two main types of service on public transport routes – headway-based and timetable-based. They differ by the frequency of service at the stops and by the information available for passengers. The required frequency of service significantly affects transport operator costs and passenger travel time which, in turn, influences the cost for a passenger. One of the ways to reduce costs for both parties of the transportation process is to make a reasonable choice of the type of service or switch between the types during the day depending on the passenger flow volume. Goal. In the paper, to justify the choice of between the types of service, the cost of public transport vehicles operation and the losses of passenger travel times are taken into account. Methodology. The developed way of making a choice about the type of service allows increasing the efficiency of urban public transport due to reducing the passenger waiting time by switching from the headway-based service in rush hours to timetable-based service in the periods of passenger flow volume decline. Results. The relationship allowing making a decision about the type of service on the route is developed. It allows to correctly introduce the type of service which will ensure the balance between the transport operator and passenger costs. Originality. The developed approach to make a decision on the type of service allows reducing the passenger waiting time by switching from headway-based service in rush hours to the timetable-based service in the periods of decline in passenger flow volume during the day. Practical value. The results of the research based on the survey data allowed estimating the numerical value of the headway at which it is expedient to switch to the timetable-based service., Проблема. На сьогодні існує два основних типи надання послуг пасажирам на маршрутах громадського транспорту – за інтер­валом руху та за розкладом руху. Вони відрізня­ються частотою обслуговування зупинок та інформацією, доступною пасажирам. Необхідна частота обслуговування громадським транспор­том суттєво впливає на витрати транспортного підприємства та час пересування пасажирів, що має вплив на вартісну оцінку вит­раченого пасажиром часу. Одним із способів змен­шення витрат для обох сторін перевізного про­цесу є обґрунтований вибір форми обслуговування пасажирів або її зміна протягом дня залежно від величини пасажиропотоку. Мета. У статті для обґрунтування вибору між формами надання послуг пасажирам вразо­вуються вартість експлуатації транспортних засобів громадського транспорту та втрати часу пасажирів на пересування. Методологія. Розроблений спосіб вибору форми надання послуг дозволяє підвищити ефективність міського громадського транспорту за рахунок скорочення часу очікування пасажирів шляхом переключення з обслуговування за інтервалом в годи­ни пік на обслуговування за розкладом в періоди спаду пасажиропотоку. Результати. Розроблена залежність, що дозволяє приймати рішення про форму надання послуг на маршруті громадського транспорту. Це дозволяє обґрунтовано запровад­жувати форму обслуговування, що забезпечить баланс між витратами транспортного перевіз­ника та пасажирів. Оригінальність. Розроблений підхід для прийняття рішення щодо форми обслу­говування дозволяє скоротити час очікування пасажирів шляхом переключення з обслуговування за інтервалом у години пік на обслуговування за розкладом у періоди зменшення величини пасажи­ропотоку протягом доби. Практичне значення. Результати дослідження, основані на даних об­стеження, дозволили оцінити чисельне значення інтервалу руху транспортних засобів громадсь­кого транспорту, коли доцільно перейти на обслуговування пасажирів за розкладом руху.

Problem. Currently, there is no universal approach to improve the efficiency of the urban public transport operation. Different methods are used during the estimation of public transport operation cost and the quality of services for the passengers. It makes actual the development of the target function which will allow assessing the carrier cost and passenger expenditures, and therefore find the balance between the interests of these parties of the transportation process. Thus, the alternative to the existing approaches can be created and then used to organize passenger transportation and improve transport enterprise management. Development of this alternative is the actual task as the new target function will open the horizon to improve the methods of organization of public transport operation. Goal. The new approach to optimize the costs of public transport operation needs to be tested for the appropriateness for the planning of passenger service in cities. Methodology. The developed target function was derived as the result of the analysis of the economic and social factors influencing the efficiency of the urban public transport operation. Results. The use of the developed target function allows finding the optimal values of cost components for the passenger and the carrier. Originality. The obtained function to optimize the performance of public transport allows reducing the costs of suboptimal use of vehicles capacity, suboptimal allocation of the vehicles to the routes and the irrational organization of vehicles operating on the routes. Practical value. The results of the research clarify the controlled and uncontrolled parameters of the public transport system operation., Проблема. На сьогодні не існує універсального підходу до оцінювання ефектив­ності функціонування міського громадського транспорту, і для оцінювання витрат на експлуатацію громадського транспорту та якості обслугову­вання пасажирів використовуються різні методи. Це робить актуальним розроблення цільової функції, яка б слугувала альтернативою наявним та доз­волила б оцінити витрати перевізника та паса­жирів і знайти баланс між інтересами цих сторін перевізного процесу. Таку альтернативну функцію можна використовувати для організації паса­жирських перевезень, удосконалення управління транспортними підприємствами та оптимізації їхніх витрат. Це завдання є актуальним, оскільки нова цільова функція дасть змогу вдоскона­лити методи організації роботи громадського транспорту в містах та підвищити якість транспортного обслуговування міського населен­ня. Мета. Новий підхід до оптимізації витрат на роботу громадського транспорту потрібно пере­вірити на придатність для використання в плану­ванні транспортного обслуговування пасажирів та організації роботи підприємств перевідників. Методологія. Розроблена цільова функція була отримана внаслідок аналізу економічних та соціальних факторів, що впливають на ефектив­ність роботи міського громадського транспорту. Результати. Використання розробленої функції дозволяє знайти оптимальні значення складових витрат пасажира громадського транспорту та перевізника. Оригінальність. Отримана функція дозволяє зменшити витрати від неоптимального використання місткості транспортних засобів громадського транспорту, неоптимального приз­начення транспортних засобів на маршрути та нераціональної організації їхньої роботи. Практичне значення. Результати дослідження уточнюють керовані та некеровані фактори, що впливають на роботу системи громадського транспорту.

Virtual Coupling (VC) is a novel train operation mode which makes trains move synchronously as a platoon via Train-to-Train (T2T) communication and they can be seen as a single train if they have same route ahead. This method dramatically enhances track capacity by decreasing headway between consecutive trains. How to realize VC operation is a hot topic recently. This paper proposes a model predictive control (MPC) system for VC to track reference driving profile or predecessor's trajectory, i.e., driving as fast as they can, to a certain extent. Finite-time horizon prediction horizon is expanded to Quasi-infinite-time prediction horizon by penalizing the last state error. Input constraints (acceleration and jerk constraints) and output constraints (safety headway constraints) are considered. This system also guarantees asymptotical stability and string stability. The results show that each train in platoon can automatically adjust its dynamic state as anticipation under safety.

To solve the problems of bus bunching and large gaps, this study combines bus holding and speed adjusting to alleviate them respectively considering the characteristics of passenger’s perceived waiting time. The difference between passenger’s perceived waiting time at stops and actual time is described quantitatively through the expected waiting time of passengers. Bus holding based on a threshold method is implemented at any stops for bunching buses, and speed adjusting based on a Markovian decision model is implemented at limited stops for lagging buses. Simulations based on real data of a bus route show that the integrated control strategy is able to improve the service reliability and to decrease passengers’ perceived waiting time at stops. Several insights have been uncovered through performance analysis: (1) The increase of holding control strength results in improvement of the headway regularity, and leads to a greater perceived waiting time though, (2) Compared to traveling freely, suitable speed guidance will not slow down the average cruising speed in the trip, (3) The scale of passenger demand and through passengers are the two key factors influencing whether a stop should be selected as a speed-adjusting control point.

The bus system is a critical component of sustainable urban transportation. However, due to the significant uncertainties in passenger demand and traffic conditions, bus operation is unstable in nature and bus bunching has become a common phenomenon that undermines the reliability and efficiency of bus services. Despite recent advances in multi-agent reinforcement learning (MARL) on traffic control, little research has focused on bus fleet control due to the tricky asynchronous characteristic -- control actions only happen when a bus arrives at a bus stop and thus agents do not act simultaneously. In this study, we formulate route-level bus fleet control as an asynchronous multi-agent reinforcement learning (ASMR) problem and extend the classical actor-critic architecture to handle the asynchronous issue. Specifically, we design a novel critic network to effectively approximate the marginal contribution for other agents, in which graph attention neural network is used to conduct inductive learning for policy evaluation. The critic structure also helps the ego agent optimize its policy more efficiently. We evaluate the proposed framework on real-world bus services and actual passenger demand derived from smart card data. Our results show that the proposed model outperforms both traditional headway-based control methods and existing MARL methods., IJCAI-2021

En el área urbana perteneciente al centro histórico de la ciudad de Huancayo, se realizaron conteos vehiculares en 8 intersecciones, con el propósito de determinar el flujo de saturación vehicular mediante dos métodos: utilizando la ecuación que emplea los factores de reducción y con el conteo en campo Headway, ambos planteados y señalados en el Highway Capacity Manual 2000, de tal manera, se obtienen dos valores de flujo de saturación vehicular para cada intersección, por lo que al dividir esos dos valores se obtiene un factor; asimismo, al realizarse los conteos vehiculares en el centro histórico de Huancayo, el término completo viene a ser factor de corrección por centro histórico, que viene a ser un valor, que al ser utilizado en la ecuación para el cálculo de flujo de saturación vehicular, nos brinda un resultado ajustado a las condiciones y realidad en la que nos encontramos actualmente en la ciudad de Huancayo. Se determinó que la hora pico en la mayoría de las intersecciones analizadas, se encuentra en horas de la noche, en un rango de 6 pm hasta las 8 pm. Estos valores de flujo de saturación vehicular ajustados a las condiciones y factores actuales en los que se encuentra la ciudad de Huancayo, muestran un mejor acercamiento a la realidad del tráfico en la que nos encontramos inmersos, siendo esto muy importante para posteriores trabajos de investigación que puedan complementarse con éste.

Perceptual markings on roads are verified with short-term effectiveness for accident prevention. However, the long-term performance of them is seldomly investigated, which unintentionally impedes its more widely recognition and application as a low-cost and readily achievable countermeasure. Also, the previous perceptual markings were only tested for speed reduction effect, little is known concerning their influence on headway adjustment. Given this, in this study, we investigated the short-, medium-, and long-term performance of the reverse linear perspective markings (RLPMs) on driving behaviors and safety benefits in car-following. The RLPMs were a form of markings pattern that can produce reverse linear perspective visual information on the lane and lead to distance underestimation. The RLPMs were permanently installed on a straight and a curve segment of a freeway in China, and the naturalistic vehicle flow data one day, four months, one year, two years, and three years after the installation of the RLPMs were collected. The statistical analyses of general and sectional relative differences of speed, distance headway and time headway suggest that 1) the speed reduced and distance and time headways increased in short-, medium-, and long-term as compared with the baseline on both the straight and curve segments; 2) the long-term performance of RLPMs significantly weakened as compared with the short-term performance, yet sustained to 0.50 m/s in speed reduction, 3.77 m in distance headway increase, and 0.097 s in time headway increase on average within the observations in one year and above on the straight segment; similar sustained performance of 0.47 m/s in speed reduction, 2.60 m in distance headway increase, and 0.072 s in time headway increase were observed on the curve segment; 3) the RLPMs were tested to have positive and relatively endured effectiveness on mitigating crash risk in car-following measured by two surrogate safety indicators based on time-to-crash (TTC) and deceleration rate to avoid a crash (DRAC). The findings of this study suggest the RLPMs could be an especially applaudable form of perceptual markings as they are relatively effective in the long-term and are multifunctional in intervening speed, distance, headway, and crash risk. This study also emphasizes the challenge of more field tests and observations on the long-term performance of the perceptual markings, and the thorough considerations of the visual perception mechanism behind the markings to achieve an alternative solution to the long-term issue.

Dvotračne izvangradske ceste u Bosni i Hercegovini (BiH) čine najveći postotak cestovne mreže i preuzimaju gotovo kompletan promet. Zbog toga se često stvaraju kolone i brzine vozila se smanjuju. Za poboljšanje kvalitete odvijanja prometa potrebno je utvrditi razinu usluge RU za postojeće stanje te za alternativne mogućnosti rekonstrukcije kritičnih elemenata cestovne mreže. RU se prema Highway Capacity Manual 2010 (HCM 2010) za dvotračne ceste definira preko mjera efikasnosti: prosječna brzina putovanja (ATS) za ceste I klase i postotak vremena provedenog u koloni (PTSF) za I i II klasu cesta. HCM pretpostavlja prevelike vrijednosti ATS-a za uvjete na magistralnim (u Hrvatskoj državnim) cestama koje odgovaraju klasi I u HCM klasifikaciji, a problem je i neujednačenost geometrije elemenata cesta, što dodatno otežava primjenu ATS-a u BiH. Stoga se u ovom radu istraživao PTSF kao primjerena mjera za određivanje efikasnosti izvangradskih dvotračnih cesta. Istraživanja provedena u svijetu pokazuju značajne razlike u rezultatima PTSF-a u odnosu na proračune prema HCM-u. U regiji nisu provedena nikakva istraživanja ove problematike i HCM se koristi u izvornom obliku. Navedeni razlozi su bili glavni motiv za istraživanje ove teme i izradu modela koji će biti jednostavno primjenjiv i u praksi. Istraživanje je provedeno za magistralne ceste s računskom brzinom 80 km/h, iz razloga što su one najvažnije u dvotračnoj cestovnoj mreži. U ovoj disertaciji je na osnovu provedenih terenskih istraživanja najprije urađena kalibracija i validacija simulacijskog softwarea Vissim 9. Razlog primjene simulacijskog softwarea je taj što on omogućuje simuliranje različitih prometnih uvjeta koji se pojavljuju na terenu ali ih je nemoguće sve obuhvatiti snimanjem ili pak za provjeru nekih novih prometnih uvjeta. Na temelju provedenih simulacija različitih prometnih uvjeta dobiven je novi model za proračun PTSF-a dvotračnih izvangradskih cesta (za brzinu 80 km/h). Dobiveni model proračuna PTSF-a validiran je na drugoj dionici i dobiveni rezultati su pokazali primjenjivost modela., In Bosnia and Herzegovina (B&H), two-lane rural highways make up the largest percentage of road network and accommodate almost complete traffic. Because of this, platoons are often formed and vehicle speeds are reduced. To improve the quality of traffic flow, it is necessary to define the level of service (LOS) for the existing condition and for alternative possibilities of reconstructing critical elements of the road network. According to Highway Capacity Manual 2010 (HCM 2010), for two-lane highways LOS is defined by measures of efficiency: average travel speed (ATS) for road class I and percent time spent following (PTSF) for road classes I and II. HCM assumes very high ATS values for conditions on national roads that are classified as class I according to HCM classification, and the problem is also nonuniformity of highway geometry elements, which further complicates the application of ATS in B&H. Therefore, PTSF was studied in this paper as an appropriate measure for determining the efficiency of two-lane rural highways. Researches carried out in the world show significant differences in PTSF results compared to the HCM calculations. No research on this topic has been conducted in the region and HCM is used in its original form. The above reasons were the main motive to study this topic and develop a model that would be easy to apply in practice. The survey was conducted on main roads with calculation speed of 80 km/h, because they are the most important in the two-lane road network. In this dissertation, calibration and validation of the Vissim 9 simulation software was first made based on conducted field research. The reason for application of the simulation software is that it allows simulation of different traffic conditions that occur in the field but cannot all be covered by surveying, or for testing some new traffic conditions. Based on the simulations of different traffic conditions, a new model for calculation of PTSF on two-lane rural roads (for speed 80 km/h) was obtained. The obtained PTSF calculation model was validated on another section and the obtained results proved the applicability of the model.

Travel time, an important traffic flow parameter, has always been a research focus and hot spot in the field of transportation. In order to predict the traffic state and evaluate the traffic efficiency of the link, the travel time is classified based on the electronic police data. First, the travel time is defined based on the electronic police work mechanism, and the relevant data is extracted from the database to make a travel time matching table of the link. We analyzed the characteristics of travel time including cycle and aggregation. Finally, 274 cuts, the traffic volume of which were more than 10, were obtained using the headway time to cut data from a certain link of Suzhou Industrial Park with the help of characteristic of cycle. The DBSCAN algorithm is used to cluster all the slices, and three categories are obtained. The travel time distribution parameters of the link are proposed based on the travel time characteristics. The relationship between the three types of cuts, the travel time distribution parameters of the link and the traffic flow parameters is analyzed and traffic state is predicted.

Traffic congestion and crash rates can be reduced by introducing variable speed limits (VSLs) and automatic incident detection (AID) systems. Previous findings based on loop detector measurements have revealed that drivers reduce their speeds while approaching traffic congestion when the AID system is active. Notwithstanding these behavioural effects, most microscopic traffic flow models assessing the impact of VSLs do not describe driver response accurately. This study analyses the main factors that influence driver deceleration behaviour while approaching traffic congestion with and without VSLs. The Dutch VSL database was linked to the driver behaviour data collected in the UDRIVE naturalistic driving study. Driver engagement in secondary tasks and glance behaviour were extracted from the video data. Linear mixed-effects models predicting the characteristics of deceleration events were estimated. The results show that the maximum deceleration is high when approaching a slower leader, when driving at high speeds and short distance headways, and close to the beginning of traffic congestion. The minimum time headway is short when driving at high speeds and changing lanes. Certain drivers showed higher decelerations and shorter time headways than others. Controlled for these main factors, smaller maximum decelerations were found when the VSLs were present and visible, and when the gantries were within close proximity. These factors could be incorporated into microscopic traffic simulations to evaluate the impact of AID systems on traffic congestion more realistically. Further research is needed to clarify the link between engagement in secondary tasks, glance behaviour and deceleration behaviour.

In this paper, we present a multi-objective simulation-based headway optimization for complex urban mass rapid transit systems. Real-world applications often confront conflicting goals of cost versus service level. We propose a two-phase algorithm that combines the single-objective covariance matrix adaptation evolution strategy with a problem-specific multi-directional local search. With a computational study, we compare our proposed method against both a multi-objective covariance matrix adaptation evolution strategy and a non-dominated sorting genetic algorithm. The integrated discrete event simulation model has several stochastic elements. Fluctuating demand (i.e., creation of passengers) is driven by hourly origin-destination-matrices based on mobile phone and infrared count data. We also consider the passenger distribution along waiting platforms and within vehicles. Our two-phase optimization scheme outperforms the comparative approaches, in terms of both spread and the accuracy of the resulting Pareto front approximation.