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Journal articles on the topic 'Traffic flow Cycling Roads Travel time (Traffic engineering)'
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1
Bahmankhah, Behnam, Paulo Fernandes, and Margarida C. Coelho. "CYCLING AT INTERSECTIONS: A MULTI-OBJECTIVE ASSESSMENT FOR TRAFFIC, EMISSIONS AND SAFETY." Transport 34, no. 3 (March 21, 2019): 225–36. http://dx.doi.org/10.3846/transport.2019.8946.
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This paper evaluated in an integrated manner the traffic performance, pollutant emissions and road conflicts between bicycles and motor vehicles at a signalized intersection. Two alternative scenarios were examined: (1) bicycles increment and motor vehicles replacement within the cycle-fixed traffic signal; (2) replacing the existing traffic control by a conventional two-lane roundabout and evaluating the impacts of bicycles increment. For each scenario, bicycle demand was varied from 9 to 270 bicycles per hour (bph). Traffic flow and vehicle dynamic data were collected from a three-leg signalized intersection in Aveiro (Portugal). The microscopic traffic model (VISSIM) paired with an emission (Vehicle Specific Power – VSP) methodology and safety (Surrogate Safety Assessment Methodology – SSAM) model were used to assess intersection-specific operations. The fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used to find the optimal bicycle demands. The results showed that two-lane roundabout outperformed the existing traffic control, namely in highest bicycle demand scenario (number of stops and travel time reduced in 78 and 14%, respectively; CO2, NOx, and HC decreased 9, 7, and 12%, respectively). It was also found that the number of conflicts was significantly reduced (–49%) with this latter layout even in maximum bicycle demand scenario (270 bph). However, roundabout layout lead to more severe conflicts and potential crashes. The analysis showed that bicycle demands of 75, 95 and 110 bph delivered good environmental and safety outcomes for the intersection.
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Leurent, Fabien M. "Analytic, Microscopic Model of Traffic Flow and Travel Time." Transportation Research Record: Journal of the Transportation Research Board 1802, no. 1 (January 2002): 233–38. http://dx.doi.org/10.3141/1802-26.
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A model of disaggregate interactions between individual vehicles was developed that makes explicit the vehicle classes, the class trip rates, and their kinematic parameters (free speed, acceleration rate, length, safety margin). Assuming exponential gaps between vehicles, analytic formulas were derived for the mean value and the variance of the path travel times within each class. The model was successively applied to one-lane roads; two-way, two-lane roads; one-way, two-lane roads; and two-way, three-lane roads.
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Cafiso, Salvatore, Carmelo D’Agostino, Mariusz Kiec, and Sylwia Pogodzinska. "Application of an Intelligent Transportation System in a Travel Time Information System: Safety Assessment and Management." Transportation Research Record: Journal of the Transportation Research Board 2635, no. 1 (January 2017): 46–54. http://dx.doi.org/10.3141/2635-06.
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The research presented here evaluated road safety on the road sections included in the Intelligent Traffic Control System of the Podhale Region (ISSRRP) in Poland. This travel time information system consists of a remote traffic microwave sensor, cameras, as well as automatic plate number recognition on national roads with variable message signs and a mobile app to suggest alternative routes in the regional road network. The study analyzed changes in safety caused by transferring traffic volume from national to regional rural and suburban road networks. The assessment of the safety performance was performed with an empirical Bayes study, with periods of three years before and after the implementation of ISSRRP. No changes were identified in the safety performance of the national road network after to the introduction of ISSRRP. However, when the overall network is considered, a potential increase in the number of crashes may be expected, depending on the volume of traffic transferred from national to regional roads, and rural or suburban areas. Therefore, a new approach for system management was proposed, taking into account not only improvement in traffic flow, but also safety performance.
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Gu, Yiming, Zhen (Sean) Qian, and Guohui Zhang. "Traffic State Estimation for Urban Road Networks Using a Link Queue Model." Transportation Research Record: Journal of the Transportation Research Board 2623, no. 1 (January 2017): 29–39. http://dx.doi.org/10.3141/2623-04.
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Traffic state estimation (TSE) is used for real-time estimation of the traffic characteristics (such as flow rate, flow speed, and flow density) of each link in a transportation network, provided with sparse observations. The complex urban road dynamics and flow entry and exit on urban roads challenge the application of TSE on large-scale urban road networks. Because of increasingly available data from various sources, such as cell phones, GPS, probe vehicles, and inductive loops, a theoretical framework is needed to fuse all data to best estimate traffic states in large-scale urban networks. In this context, a Bayesian probabilistic model to estimate traffic states is proposed, along with an expectation–maximization extended Kalman filter (EM-EKF) algorithm. The model incorporates a mesoscopic traffic flow propagation model (the link queue model) that can be computationally efficient for large-scale networks. The Bayesian framework can seamlessly integrate multiple data sources for best inferring flow propagation and flow entry and exit along roads. A synthetic test bed was created. The experiments show that the EM-EKF algorithm can promptly estimate traffic states. Another advantage is that the EM-EKF can update its model parameters in real time to adapt to unknown traffic incidents, such as lane closures. Finally, the proposed methodology was applied to estimating travel speed for an urban network in the Washington, D.C., area and resulted in satisfactory estimation results with an 8.5% error rate.
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Yang, Funing, Guoliang Liu, Liping Huang, and Cheng Siong Chin. "Tensor Decomposition for Spatial—Temporal Traffic Flow Prediction with Sparse Data." Sensors 20, no. 21 (October 24, 2020): 6046. http://dx.doi.org/10.3390/s20216046.
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Urban transport traffic surveillance is of great importance for public traffic control and personal travel path planning. Effective and efficient traffic flow prediction is helpful to optimize these real applications. The main challenge of traffic flow prediction is the data sparsity problem, meaning that traffic flow on some roads or of certain periods cannot be monitored. This paper presents a transport traffic prediction method that leverages the spatial and temporal correlation of transportation traffic to tackle this problem. We first propose to model the traffic flow using a fourth-order tensor, which incorporates the location, the time of day, the day of the week, and the week of the month. Based on the constructed traffic flow tensor, we either propose a model to estimate the correlation in each dimension of the tensor. Furthermore, we utilize the gradient descent strategy to design a traffic flow prediction algorithm that is capable of tackling the data sparsity problem from the spatial and temporal perspectives of the traffic pattern. To validate the proposed traffic prediction method, case studies using real-work datasets are constructed, and the results demonstrate that the prediction accuracy of our proposed method outperforms the baselines. The accuracy decreases the least with the percentage of missing data increasing, including the situation of data being missing on neighboring roads in one or continuous multi-days. This certifies that the proposed prediction method can be utilized for sparse data-based transportation traffic surveillance.
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Gu, Jian, Miaohua Li, Linghua Yu, Shun Li, and Kejun Long. "Analysis on Link Travel Time Estimation considering Time Headway Based on Urban Road RFID Data." Journal of Advanced Transportation 2021 (April 13, 2021): 1–19. http://dx.doi.org/10.1155/2021/8876626.
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In this paper, the calculation method of the link travel time is firstly analysed in the continuous traffic flow by using the detection data collected when vehicles pass through urban links, and a theoretical derivation formula for estimating link travel time is proposed by considering the typical vehicle travel time and the time headway deviation upstream and downstream of the links as the main parameters. A typical vehicle analysis method based on link travel time similarity is proposed, and the theoretical formula is optimized, respectively. Then, an estimation formula based on maximum travel time similarity and an estimation formula based on maximum travel time confidence interval similarity are proposed, respectively. Finally, when analysing the fitting conditions, the collected data from urban roads in Nanjing are used to verify the proposed travel time estimation method based on the radio frequency identification devices. The results show that time headway deviation converges to zero when the hourly vehicle volume is more than 20 veh/h in the certain flow direction, and there are more positive and negative fluctuations when the hourly vehicle volume is less than 10 veh/h in the certain flow direction. The accuracy of the proposed improved method based on typical vehicle travel time estimation is significantly improved by considering the typical vehicle travel time, and typical vehicles on the road segment mainly exist at the tail of the traffic platoon in the corresponding period.
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Das, Aathira K., and Bhargava Rama Chilukuri. "Link Cost Function and Link Capacity for Mixed Traffic Networks." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 9 (June 24, 2020): 38–50. http://dx.doi.org/10.1177/0361198120926454.
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Link cost function and link capacity are critical factors in traffic assignment modeling. Popular link cost functions like the Bureau of Public Roads (BPR) function have well-known drawbacks and are not suitable for mixed traffic conditions where a variety of vehicle classes use the road in a non-lane-based movement. Similarly, capacity is generally considered as a constant value. However, in mixed traffic conditions, capacity is not constant, but a function of vehicle class composition. Toward addressing these issues, this paper proposes a link cost function in relation to link travel time and link capacity in relation to vehicular traffic flow for mixed traffic conditions. The functions are developed based on the kinematic wave model, which is popularly used for estimating traffic dynamics on the roads. The developed link cost function and link capacity use field measurable parameters that incorporate mixed traffic features. The functions are validated against empirical data obtained from 12 signal cycles from two different signalized intersections in Chennai, India, representing different scenarios of mixed traffic, and it was found that the results match well with the empirical data.
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Zhao, Fei, Liping Fu, Ming Zhong, Shaobo Liu, Xudong Wang, Junda Huang, and Xiaofeng Ma. "Development and Validation of Improved Impedance Functions for Roads with Mixed Traffic Using Taxi GPS Trajectory Data and Simulation." Journal of Advanced Transportation 2020 (February 21, 2020): 1–12. http://dx.doi.org/10.1155/2020/7523423.
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This paper proposes an improved impedance function for roads with mixed traffic. It is known that only limited studies consider the impact of nonmotorized traffic on travel impedance of a road segment, and a comparison of the impedance considering nonmotorized traffic with the classic BPR function, which does not consider the former, is scarce. Most of the previous studies targeted road conditions in developed countries, where the presence of nonmotorized traffic is negligible, and therefore limited efforts have been invested to develop improved impedance function considering mixed traffic. To overcome this limitation, this paper develops an improved impedance function and carries out a case study for a road in the city of Wuhan, China. The improved impedance function explicitly considers the interaction between motorized and nonmotorized traffic. Taxi GPS data from the case study road is used to extract and analyze the travel time of the “probe vehicles” running through the sampled segment at any time during a sampling day. The capacity of the road segment is measured, and the traffic flow of motorized vehicles and nonmotorized vehicles on the segment is counted. Based on the above data, the classic BPR function and the improved one proposed in this paper are calibrated. After comparing and analyzing the observed road impedance based on both analytical and simulation results, the classic BPR function and the proposed impedance function, the proposed impedance function is found to be more accurate to simulate the observed road impedance, with the error reducing from 14.83 s with the classic BPR impedance function to 6.50 s with the improved function. The proposed impedance function possesses a simple structure and high flexibility, and the parameters calibrated in this paper can be applied to similar roads to provide more realistic impedance than the previous ones based on the classic BPR function. The calibrated improved impedance function’s transferability to other similar roads is validated by applying it to another road and the results show that the percentage error between the predicted travel times and the observed ones is only 3.8%.
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Quessada, Matheus S., Rickson S. Pereira, William Revejes, Bruno Sartori, Euclydes N. Gottsfritz, Douglas D. Lieira, Marco AC da Silva, Geraldo P. Rocha Filho, and Rodolfo I. Meneguette. "ITSMEI: An intelligent transport system for monitoring traffic and event information." International Journal of Distributed Sensor Networks 16, no. 10 (October 2020): 155014772096375. http://dx.doi.org/10.1177/1550147720963751.
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The disorderly growth of urban centers can lead to serious socioeconomic disadvantages, such as health problems, due to long-term exposure to toxic gases and also monetary losses due to time stopped in congestion. Thus, there is a need for systems that help in the management and control of the flow of vehicles on the roads, seeking to reduce the damage resulting from a faulty transportation system and also avoiding the use of an inefficient system of information dissemination of urban roads. In this scenario, innovative systems are being developed to analyze the conjunction of road conditions to supervise and provide routes as needed for drivers to provide greater comfort and safety to vehicle traffic on urban roads. Thus, in this work, we propose the development of a system to monitor vehicle traffic, informing about events that are taking place on the roads in real time. The system can recommend new routes to drivers or allow drivers to take action based on information received from a particular road. As well as, the system uses driver location information for traffic monitoring, which will later be available for any devices, either a mobile device (smartphone) or a desktop. For the evaluation of the proposed system, a user case was developed for the Catanduva city in which we performed a test with the proposed system and was possible to verify a reduction in vehicle stopping time by 42% and a shorter travel time of 50% with an average speed of 33 km/h.
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Namoun, Abdallah, Ali Tufail, Nikolay Mehandjiev, Ahmed Alrehaili, Javad Akhlaghinia, and Evtim Peytchev. "An Eco-Friendly Multimodal Route Guidance System for Urban Areas Using Multi-Agent Technology." Applied Sciences 11, no. 5 (February 25, 2021): 2057. http://dx.doi.org/10.3390/app11052057.
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The use and coordination of multiple modes of travel efficiently, although beneficial, remains an overarching challenge for urban cities. This paper implements a distributed architecture of an eco-friendly transport guidance system by employing the agent-based paradigm. The paradigm uses software agents to model and represent the complex transport infrastructure of urban environments, including roads, buses, trolleybuses, metros, trams, bicycles, and walking. The system exploits live traffic data (e.g., traffic flow, density, and CO2 emissions) collected from multiple data sources (e.g., road sensors and SCOOT) to provide multimodal route recommendations for travelers through a dedicated application. Moreover, the proposed system empowers the transport management authorities to monitor the traffic flow and conditions of a city in real-time through a dedicated web visualization. We exhibit the advantages of using different types of agents to represent the versatile nature of transport networks and realize the concept of smart transportation. Commuters are supplied with multimodal routes that endeavor to reduce travel times and transport carbon footprint. A technical simulation was executed using various parameters to demonstrate the scalability of our multimodal traffic management architecture. Subsequently, two real user trials were carried out in Nottingham (United Kingdom) and Sofia (Bulgaria) to show the practicality and ease of use of our multimodal travel information system in providing eco-friendly route guidance. Our validation results demonstrate the effectiveness of personalized multimodal route guidance in inducing a positive travel behavior change and the ability of the agent-based route planning system to scale to satisfy the requirements of traffic infrastructure in diverse urban environments.
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Yang, Xin, Juncheng Chen, Mantun Yan, Zhao He, Ziyan Qin, and Jiandong Zhao. "Regional Boundary Control of Traffic Network Based on MFD and FR-PID." Journal of Advanced Transportation 2021 (September 3, 2021): 1–12. http://dx.doi.org/10.1155/2021/9730813.
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In recent years, urban traffic congestion has become more serious and the capacity of roads has declined, resulting in frequent traffic accidents. In order to effectively alleviate the traffic congestion of the regional road network, aiming at the problem of lack of accurate OD data of the road network, a regional boundary control method of the traffic network based on fuzzy RBF neural network PID (FR-PID) is proposed by combining the theory of macroscopic fundamental diagram (MFD). Firstly, based on the traffic survey, the simulation model of the study area is built, and the basic data such as the traffic flow and the time occupation rate of each road section are obtained. Secondly, the simulation data are used to test the existence of MFD in the road network, and the controlled area is defined. Then, the vehicle change model of the road network area is established. Then, in view of the problem of poor adaptive ability of traditional PID control, the FR-PID control structure is designed. Finally, an example is verified by VISSIM software. In the simulation, different control methods are used for comparison and verification, and the simulation results are analyzed. The results show that the control effect of the proposed method is better than that of the traditional method, and the regional average accumulative vehicle number, regional average completed volume, regional accumulative delays, and total vehicle travel time are optimized by 28.21%, 41.19%, 27.06%, and 32.73%, respectively. The research results can provide reference for the management of urban congestion, thereby reducing the number of traffic accidents and improving urban traffic safety.
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Liang, Xiao, Gonçalo Homem de Almeida Correia, and Bart van Arem. "Applying a Model for Trip Assignment and Dynamic Routing of Automated Taxis with Congestion: System Performance in the City of Delft, The Netherlands." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 8 (May 4, 2018): 588–98. http://dx.doi.org/10.1177/0361198118758048.
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This paper proposes a method of assigning trips to automated taxis (ATs) and designing the routes of those vehicles in an urban road network, and also considering the traffic congestion caused by this dynamic responsive service. The system is envisioned to provide a seamless door-to-door service within a city area for all passenger origins and destinations. An integer programming model is proposed to define the routing of the vehicles according to a profit maximization function, depending on the dynamic travel times, which varies with the ATs’ flow. This will be especially important when the number of automated vehicles (AVs) circulating on the roads is high enough that their routing will cause delays. This system should be able to serve not only the reserved travel requests, but also some real-time requests. A rolling horizon scheme is used to divide one day into several periods in which both the real-time and the booked demand will be considered together. The model was applied to the real size case study city of Delft, the Netherlands. The results allow assessing of the impact of the ATs movements on traffic congestion and the profitability of the system. From this case-study, it is possible to conclude that taking into account the effect of the vehicle flows on travel time leads to changes in the system profit, the satisfied percentage and the driving distance of the vehicles, which highlights the importance of this type of model in the assessment of the operational effects of ATs in the future.
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Alfaseeh, Lama, and Bilal Farooq. "Multi-Factor Taxonomy of Eco-Routing Models and Future Outlook." Journal of Sensors 2020 (January 11, 2020): 1–10. http://dx.doi.org/10.1155/2020/4362493.
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Traditionally, routing decisions have been based on minimizing travel time as the associated cost. Eco-routing considers the environmental aspects (e.g., emissions and fuel) as part of the travel cost to mitigate the undesirable impact of transportation systems on the environment. Unlike the existing eco-routing review papers, this research work is aimed at providing a three-factor taxonomy at a more disaggregated level from the optimization perspective and map eco-routing studies to the proposed taxonomy. Furthermore, the strengths and weaknesses of the presented models are summarized. Our main findings include (a) a majority of studies optimized one objective at a time; (b) the microscopic level of aggregation of the flow and emission/fuel models was rarely employed for large case studies, due to the associated complexity; and (c) all of the reviewed studies were applied in a centralized routing system environment. In the near future, when intelligent vehicles will be on the roads, a multi-objective distributed routing framework can be employed with a microscopic level of aggregation for both traffic and emission models, which is capable of operating on largescale networks in real time. Additionally, short-term spatiotemporal prediction of GHG cost is a crucial aspect to be tackled.
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Bhuyan, Prasanta Kumar, and Smruti Sourava Mohapatra. "AFFINITY PROPAGATION CLUSTERING IN DEFINING LEVEL OF SERVICE CRITERIA OF URBAN STREETS." TRANSPORT 29, no. 4 (December 16, 2014): 401–11. http://dx.doi.org/10.3846/16484142.2014.984242.
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Defining Level Of Service (LOS) criteria is very important as this is the first step of LOS analysis but this is not well defined in Indian context. The analysis followed in India is basically adaptation of Highway Capacity Manual (HCM 2000) methodology which is more suitable for developed countries having homogenous traffic pattern. An attempt has been made in this study to define LOS criteria of urban streets for developing countries having heterogeneous traffic flow condition. Defining LOS is basically a classification problem and to solve it Affinity Propagation (AP), a very recently developed cluster algorithm is used. Inventory details and the required speed data are collected from five major street corridors of Greater Mumbai Region in India through the application of Trimble GeoXT Global Positioning System (GPS) receiver. Six validation parameters are used on Free Flow Speed (FFS) data to find the optimal number of clusters, which is required for the classification of street segments into number of classes. After that speed data collected during both peak and off-peak hours are averaged over street segments and clustered into six groups to get the speed ranges of different LOS categories. Using validation parameters, considering the physical and surrounding environmental characteristics it is found that street segments can be classified into four classes in Indian context as mentioned in Highway Capacity Manual 2000. However, the FFS range for urban street class IV (urban design category) is significantly lower because of varying road geometric characteristics. The speed ranges of LOS categories under urban street classes are proportionately lower to that values mentioned in HCM 2000 because of highly heterogeneous traffic flow on urban Indian roads. The travel speed data collection procedure using GPS is simple and accurate. In addition, AP clustering is highly efficient in terms of time saving and provides a very accurate solution to classification problems. Hence, both GPS and AP techniques can be applied in other countries to define the speed ranges of LOS categories considering the local conditions.
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Farooq, Asim, Mowen Xie, Edward J. Williams, Vimal Kr Gahlot, Du Yan, and Zhou Yi. "Downsizing Strategy for Cars, Beijing for People Not for Cars: Planning for People." Periodica Polytechnica Transportation Engineering 46, no. 1 (October 30, 2017): 50. http://dx.doi.org/10.3311/pptr.10851.
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Beijing, the capital of China, is increasing enormously relative to its economy, pollution, population and dependency on private vehicles. Most of the Chinese cities are built and being built as a car-centric city. Six million cars are registered in Beijing, and with passage of time the attraction of private vehicles increases. Increasing in infrastructure the selection towards private vehicle is boosting. Municipality of Beijing is busy to use the conventional ways to solve the congestion problem rather than the smart solution, what megacities need to adopt. Beijing is second-worst in length of communing time. This paper addresses the traffic congestion problem in the central part of the Beijing by using “Mixed Use Small Block Concept”, where the network of roads spreads like veins in a human body, and the accessibility around center is dependent on vehicle. The aim is to recover the areas from cars and give it to residential and improve their accessibility by changing the mode of travel from car to walking and cycling, and provide clear boundaries and redesign the area by using Small Block Mixed use concept. Combining the public transportation, urban planning design and Non-Motorized Transportation priority will lead the city towards livability.The right to access every building in the city by private motorcars actually the right to destroy the city.” Mumford.
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OSMAN, Hesham, Marwan AMMAR, and Moheeb EL-SAID. "OPTIMAL SCHEDULING OF WATER NETWORK REPAIR CREWS CONSIDERING MULTIPLE OBJECTIVES." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 23, no. 1 (January 19, 2017): 28–36. http://dx.doi.org/10.3846/13923730.2014.948911.
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Water main breaks disrupt water services and impact traffic flow along congested city roads. Dispatching water pipe repair crews needs to consider several factors that include: 1) the priority of repair site; 2) the suitability and efficiency of the construction crew in repairing a particular break type; and 3) the time required for crews to travel between break sites. This paper presents a simulation-based multi-objective optimization model to schedule repair crews across water network break sites in an urban setting. Discrete-event simulation models for the water pipe repair process are developed to account for various repair methods. These models are subsequently integrated within a GA-based multi-objective optimization model that considers the following objectives: 1) minimizing the total repair time required to complete all breaks; 2) minimizing the total cost to complete the breaks; and 3) minimizing the cumulative impact of all breaks incident on road users and water customers. A case study for the water network on the City of Damietta, Egypt is used to demonstrate the capabilities of the model. Results show a 21% reduction in repair time and 50% reduction in user impact compared to heuristic crew allocation methods used by the water utility.
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Schaefer, Jaclyn S., Miguel A. Figliozzi, and Avinash Unnikrishnan. "Empirical Study of the Impacts of Bicycles on Passenger Car Speeds on Urban Roads without Bicycle Lanes." Transportation Research Record: Journal of the Transportation Research Board, March 31, 2021, 036119812110041. http://dx.doi.org/10.1177/03611981211004122.
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Higher bicycle mode share has been suggested as part of a solution to reduce the burden of congestion in urban areas. As strategies to promote cycling are implemented, concerns have been raised by some road users and stakeholders citing simulation-based traffic studies that indicate that an increase in the bicycle mode share generates major travel time delays via reduced vehicle speeds unless bicycle lanes are provided. The current research investigates the effects bicycles may have on motorized vehicle speeds on a variety of lower speed and volume urban roads without bicycle lanes. A detailed comparative analysis of passenger car speeds was performed using two vehicle scenarios: (i) a passenger car that was preceded by a bicycle; and (ii) a passenger car that was preceded by another passenger car. The mean and 85th percentile speeds of scenarios (i) and (ii) were analyzed using t-tests. Relationships between speed and gap times with oncoming (opposite direction) traffic were also investigated. The results indicate that, at most sites (92%), bicycles do not reduce passenger car mean speeds by more than 1 mph. Speed reductions are not generally observed in local streets or facilities with adequate gaps in oncoming traffic for overtaking.