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1Evaluating the Impacts of Speed Limit Increases on Rural Two-Lane Highways Using Quantile Regression
المؤلفون: Shakir Mahmud, Eva Kassens-Noor, Hisham Jashami, Babak Safaei, Timothy J. Gates, Nischal Gupta, Peter T. Savolainen
المصدر: Transportation Research Record: Journal of the Transportation Research Board. 2675:740-753
مصطلحات موضوعية: 050210 logistics & transportation, 0303 health sciences, bepress|Engineering, Mechanical Engineering, Speed limit, 05 social sciences, bepress|Engineering|Civil and Environmental Engineering|Transportation Engineering, engrXiv|Engineering|Civil and Environmental Engineering|Transportation Engineering, Quantile regression, 03 medical and health sciences, engrXiv|Engineering, bepress|Engineering|Civil and Environmental Engineering, 0502 economics and business, engrXiv|Engineering|Civil and Environmental Engineering, Econometrics, Selection (genetic algorithm), 030304 developmental biology, Civil and Structural Engineering, Mathematics
الوصف: Understanding speed selection behavior of drivers following speed limit increases is critically important. To date, the literature has largely focused on freeways and the effects of speed limit changes on two-lane highways remains under researched. Prior research has generally focused on changes to mean speeds, although the speeds of both the highest and lowest drivers are also of great interest. This study investigates trends in free-flow travel speeds following 2017 legislation that increased the posted speed limit from 55 to 65 mph on 943 mi of rural highways in Michigan. Speed data were collected for over 46,000 drivers at 67 increase segments where speed limit increased and 28 control segments where speed limits remained unchanged, before and during each of the two successive years following the speed limit increases. Site-specific traffic, geometric, and cross-sectional information was also collected. Impacts of the speed limit increases on the 15th, 50th, and 85th percentile speeds were evaluated using quantile regression. Separate analyses were conducted for passenger cars and heavy vehicles. Locations where the speed limits were raised experienced increases in travel speeds ranging from 2.8 to 4.8 mph. The control sites experienced marginal changes in speeds, which suggests that any spillover effects of the higher speed limits have been limited. Significant differences were observed across the quantiles with respect to the effects of the speed limit increases, as well as numerous site-specific variables of interest. The results provide important insights about the nature of driver speed selection and the impacts of speed limit increases.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a890d6ede1cec2b0aeb313f7f2bebcc6
https://doi.org/10.1177/03611981211019732 -
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المؤلفون: Satish Chandra, Mithun Mohan
المصدر: International Journal of Transportation Science and Technology, Vol 10, Iss 4, Pp 393-401 (2021)
مصطلحات موضوعية: Occupancy, Process (engineering), Computer science, Unsignalized intersection, Flow (psychology), Critical gap, Transportation, 010501 environmental sciences, Management, Monitoring, Policy and Law, 01 natural sciences, Transport engineering, 0502 economics and business, 0105 earth and related environmental sciences, Civil and Structural Engineering, 050210 logistics & transportation, TA1001-1280, Driver behaviour, 05 social sciences, Regression analysis, Transportation engineering, Occupancy time method, Automotive Engineering, Traffic conditions, Heterogeneous traffic, Videography, Intersection (aeronautics)
الوصف: The choice to accept or reject an available gap at unsignalized intersections depends on several factors that include driver and vehicle characteristics, intersection geometry, weather conditions, etc. Although drivers in heterogeneous traffic conditions accept shorter gaps than their counterparts in developed countries, they are reluctant to accept the same gap offered by a large-sized vehicle instead of a smaller vehicle. This influence of traffic stream’s composition on the critical gap is not well-established. The present research attempts to quantify this influence by realizing its importance, especially under heterogeneous traffic conditions. Data were collected from six unsignalized intersections located in different parts of India through videography. Details about gaps and lags which were accepted and rejected, types of vehicles involved in the gap acceptance process, and the amount of conflicting traffic faced by each of the turning vehicles were extracted from the recorded videos. Critical gaps for different vehicle types making right-turns at each of the intersections were estimated based on Occupancy Time Method. Further, a non-linear regression revealed that the estimated critical gaps vary logarithmically with the percentage of large-sized vehicles in the conflicting flows. Based on these relationships, the base values of the critical gap and the adjustment for the proportion of large-sized vehicles in conflicting flows are estimated for turning movements at unsignalized intersections in heterogeneous traffic conditions. These relationships will be useful in assessing the capacity of unsignalized intersections of developing countries.
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المصدر: International Journal of Transportation Science and Technology, Vol 10, Iss 4, Pp 342-352 (2021)
مصطلحات موضوعية: Aviation, media_common.quotation_subject, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Transportation, Sample (statistics), Plan (drawing), 010501 environmental sciences, Management, Monitoring, Policy and Law, 01 natural sciences, Confirmatory factor analysis, Transport engineering, ComputerApplications_MISCELLANEOUS, Passengers’ expectation, 0502 economics and business, Quality (business), Quality management, Set (psychology), 0105 earth and related environmental sciences, Civil and Structural Engineering, media_common, 050210 logistics & transportation, Service quality, TA1001-1280, business.industry, 05 social sciences, Transportation engineering, Airport service quality, Automotive Engineering, Airport developments, Business, Sustainable growth rate
الوصف: The Thai aviation industry is projected to maintain steady growth due to an increase in flights and passengers, which will be supported by expanded air transport infrastructure. Along with handling the logistical demands imposed by increased traffic, airports must improve their quality of services, efficiency, and attentiveness to passengers’ needs so as to maintain high customer ratings. The objective of this study was to create a model for measuring airport quality by using confirmatory factor analysis to identify passengers’ expectations. The sample consisted of 1037 randomly selected passengers flying on domestic Thai airlines. The resulting model consists of seven dimensions of service quality: security, check-in, wayfinding, airport environment, access, arrival services, and airport facilities. This set of dimensions is complementary to previous research and can help airport regulators to better understand the actual needs of airport users and plan airport development accordingly. To strengthen Thailand’s economy within a framework of sustainable growth, it is important to provide passengers with more attractive services so that they will become repeat customers.
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المؤلفون: Mohammad Azadi, Mana Motamedi, Gholamali Shafabakhsh
المصدر: Journal of Traffic and Transportation Engineering (English ed. Online), Vol 8, Iss 6, Pp 1036-1048 (2021)
مصطلحات موضوعية: Polyurethane, Materials science, Asphalt binder, Rut, 0211 other engineering and technologies, Modulus, Transportation, 02 engineering and technology, engineering.material, chemistry.chemical_compound, Filler (materials), 021105 building & construction, 0502 economics and business, Composite material, Fatigue parameter, Civil and Structural Engineering, 050210 logistics & transportation, TA1001-1280, 05 social sciences, Phase angle, Road engineering, Rutting resistance, Transportation engineering, Mastic, chemistry, Creep, Asphalt, Dynamic shear rheometer, engineering
الوصف: Fatigue and rutting phenomena are major distresses in asphalt pavements. Asphalt mixture properties are highly dependent upon the asphalt binder and the mastic behavior. The purpose of this study was to investigate the behavior of the asphalt binder and the mastic, modified by the synthesized polyurethane, at high and intermediate temperatures. The filler/asphalt binder ratio (by weight) was 1.0. The dynamic shear rheometer (DSR) was used to measure fatigue (G∗sin δ) and rutting (G∗/sin δ) parameters. In this study, the multiple stress creep and recovery (MSCR) test was also utilized to calculate the rutting potential of the asphalt binder and the mastic. Parameters of the non-recoverable compliance (Jnr) and the percentage recovery (%) were evaluated at high temperatures. The obtained results indicated that the synthesized polyurethane improved the rutting and fatigue properties. There was a significant correlation between the asphalt binder and the mastic in terms of the complex modulus (R2 = 0.9958), rutting (R2 = 0.9944), and the non-recoverable compliance (R2 = 0.9707). For the fatigue parameter (R2 = 0.9852), the complex modulus (R2 = 0.9855), and the phase angle (R2 = 0.8262), significant relationships were observed between the asphalt binder and mastic samples at intermediate temperatures. Overall, the chemical reaction between the filler and the asphalt binder could be effective in different behaviors of the mastic and asphalt binder. There was a 112%–164% increase in the G∗sin δ parameter for mastics, compared to that of the asphalt binder. The complex modulus was 6 times higher by adding the filler content.
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المؤلفون: Yanhai Wang, Junhua Xiao, De Zhang, Siqi Sun, Kai Wei, Xiao Zhang
المصدر: International Journal of Transportation Science and Technology, Vol 10, Iss 4, Pp 313-328 (2021)
مصطلحات موضوعية: Materials science, Transportation, 010501 environmental sciences, Management, Monitoring, Policy and Law, Granular material, 01 natural sciences, 0502 economics and business, FDM-DEM coupling method, Surface layer, Composite material, Force chain, Macro and meso analysis, 0105 earth and related environmental sciences, Civil and Structural Engineering, 050210 logistics & transportation, TA1001-1280, 05 social sciences, Subgrade, Vibration, Transportation engineering, High speed railway (HSR), Ballastless track subgrade, Dynamic loading, Macroscopic scale, Automotive Engineering, Random vibration
الوصف: Considering the discrete and stochastic properties of granular materials, a two-dimensional numerical model was established to study the dynamic behavior of high-speed railway (HSR) ballastless track subgrade by using finite difference-discrete element (FDM-DEM) coupling method. Combined with on-site vibration test results in macroscopic scale, the mesoscopic vibration response of subgrade granular materials was analyzed under different speed levels. Some unusual phenomena were observed as follow: 1). In the surface layer (i.e., the top area of the subgrade, thickness = 0.4 m), particles showed a very wide response band in the frequency domain (up to 130 Hz), even beyond the maximum frequency of train loading (60 Hz). It was found that some particles in the surface layer produced not only forced vibration, but also local random vibration. However, the bottom layer particles (i.e., the area under the surface layer, thickness = 2.3 m) were only active within 40 Hz. 2) Force chains in the granular aggregate were disappeared and rebuilt synchronously in the dynamic loading process. A typical mode of force chain weakening was described in meso scale. 3) Particles at interface region between the surface and bottom layer exhibited severe local vibration amplification when the train speed level was higher than 300 km/h.
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المؤلفون: Feng Chen, Young-Ji Byon, Xiaoxiang Ma, Bowen Dong, Peiyan Chen, Ming Zhu
المصدر: International Journal of Transportation Science and Technology, Vol 10, Iss 4, Pp 329-341 (2021)
مصطلحات موضوعية: Truck, Computer science, Transportation, Crash, 010501 environmental sciences, Management, Monitoring, Policy and Law, 01 natural sciences, Bridge (interpersonal), Wind speed, Long-span bridge crash, 0502 economics and business, Oversampling, Bridge structure movement, 0105 earth and related environmental sciences, Civil and Structural Engineering, Structure (mathematical logic), 050210 logistics & transportation, TA1001-1280, Movement (music), business.industry, 05 social sciences, Structural engineering, Traffic safety, Transportation engineering, Automotive Engineering, Classification methods, business, Over-sampling classification
الوصف: In comparison to ordinary highways, traffic accidents on long-span bridges have unique characteristics due to large percentages of large trucks, inclement weather conditions, and dynamically moving bridge structures. Presently, there is a research significant gap in the existing literature about the traffic safety of long-span bridges due to those difficulties. Meanwhile, the structure movement data of bridge is difficult to obtain. In this paper, real-time data related to the bridge crashes including surrounding environment, traffic status and especially structural movement were obtained from monitoring system of a long-span bridge. An oversampling-based classification method was utilized to explore the risk factors of the long-span bridge crashes. The results indicate that higher maximum wind speed and volume prior to a crash tend to increase the likelihood of the occurrences of the crash, while higher temperature, humidity, average vehicle speed and truck percentage are found to decrease the likelihood. Moreover, the structure movement indicators including horizontal vibration acceleration and deformation are found to have significant adverse effects on the traffic safety of the long-span bridge, and we recommend that those factors should be considered at the design stage.
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المؤلفون: Azim Eskandarian, Goodarz Mehr
المصدر: International Journal of Transportation Science and Technology, Vol 10, Iss 4, Pp 353-365 (2021)
مصطلحات موضوعية: Computer science, Real-time computing, Transportation, Probability estimation, Systems and Control (eess.SY), 010501 environmental sciences, Management, Monitoring, Policy and Law, Electrical Engineering and Systems Science - Systems and Control, 01 natural sciences, Parameter analysis, Reduction (complexity), Lane drop, 0502 economics and business, Headway, Lane change, FOS: Electrical engineering, electronic engineering, information engineering, 0105 earth and related environmental sciences, Civil and Structural Engineering, eess.SY, 050210 logistics & transportation, TA1001-1280, Warning system, Traffic simulation, 05 social sciences, Probabilistic logic, Traffic flow, cs.SY, Transportation engineering, Automotive Engineering, Drop (telecommunication)
الوصف: This paper proposes an onboard advance warning system based on a probabilistic prediction model that advises vehicles on when to change lanes for an upcoming lane drop. Using several traffic- and driver-related parameters such as the distribution of inter-vehicle headway distances, the prediction model calculates the likelihood of utilizing one or multiple lane changes to successfully reach a target position on the road. When approaching a lane drop, the onboard system projects current vehicle conditions into the future and uses the model to continuously estimate the success probability of changing lanes before reaching the lane-end, and advises the driver or autonomous vehicle to start a lane changing maneuver when that probability drops below a certain threshold. In a simulation case study, the proposed system was used on a segment of the I-81 interstate highway with two lane drops - transitioning from four lanes to two lanes - to advise vehicles on avoiding the lane drops. The results indicate that the proposed system can reduce average delay by up to 50% and maximum delay by up to 33%, depending on traffic flow and the ratio of vehicles equipped with the advance warning system.
Manuscript accepted for publication in the International Journal of Transportation Science and Technology. This manuscript version is made available under the CC-BY-NC-ND 4.0 license (http://creativecommons.org/licenses/by-nc-nd/4.0/)وصف الملف: application/pdf
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المؤلفون: Randolph Kirchain, Jeremy Gregory, Fengdi Guo, Xingang Zhao
المصدر: International Journal of Pavement Engineering. 23:2631-2643
مصطلحات موضوعية: 050210 logistics & transportation, engrXiv|Engineering|Civil and Environmental Engineering|Civil Engineering, Artificial neural network, bepress|Engineering, Computer science, 05 social sciences, 0211 other engineering and technologies, Pavement management, bepress|Engineering|Civil and Environmental Engineering|Transportation Engineering, engrXiv|Engineering|Civil and Environmental Engineering|Transportation Engineering, 02 engineering and technology, bepress|Engineering|Civil and Environmental Engineering|Civil Engineering, computer.software_genre, engrXiv|Engineering, bepress|Engineering|Civil and Environmental Engineering, Mechanics of Materials, 021105 building & construction, 0502 economics and business, engrXiv|Engineering|Civil and Environmental Engineering, Multi output, Data mining, computer, Civil and Structural Engineering
الوصف: A novel weighted multi-output neural network (NN) model is proposed for predicting the deterioration of rigid pavements based on Iowa pavement management system data. This first-of-a-kind model simultaneously predicts four pavement condition metrics concerning rigid pavements, including IRI, faulting, longitudinal crack and transverse crack. It provides an opportunity to efficiently evaluate pavement conditions and to make treatment decisions based on multi-condition metrics, such as the pavement condition index (PCI) for budget allocation models. Compared to traditional single-output NN models, this multi-output model is capable of incorporating correlations among different condition metrics. During model training, each condition metric is assigned a weight to reflect its relative importance. When the weights equal to those in the formula for the multi-condition metric, the prediction performance for PCI is optimal (13% lower MSE than optimal, single-output models). The multi-output model improves on the prediction performance for three of the four individual condition metrics compared to optimal single-output models. Results show that the consideration of correlations could improve the prediction performance for single and multi-condition metrics. Finally, variable weighting is critical for achieving the optimal balance of prediction performance among the various metrics as dictated by the needs of the decisionmaker.
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المؤلفون: Farshid Safari, Erfan Hassannayebi, Hamid Mirzahossein
المصدر: Journal of Traffic and Transportation Engineering (English ed. Online), Vol 8, Iss 5, Pp 751-761 (2021)
مصطلحات موضوعية: Pollution, media_common.quotation_subject, 0211 other engineering and technologies, Air pollution, Transportation, 02 engineering and technology, medicine.disease_cause, Admissible traffic flow, Traffic engineering, Transport engineering, Highway Capacity Manual, 021105 building & construction, 0502 economics and business, medicine, Environmental capacity estimation, Civil and Structural Engineering, media_common, 050210 logistics & transportation, TA1001-1280, Noise pollution, business.industry, 05 social sciences, Highway capacity manual (HCM), Environmental pollutions, Traffic flow, Transportation engineering, Noise, Environmental science, Road pricing, business
الوصف: In this paper, the concept of environmental capacity is developed to identify a convenient maximum traffic volume which will not reduce the life quality of residents. The presented method investigates the idea of traffic capacity under environmental constraints by calculating the maximum number of vehicles allowed on roads based on acceptable levels of air and noise pollutants. In this study, the permissible noise pollution level and permissible levels of CO and NOx pollution are considered for determining environmental capacity. Results show the significant difference between environmental capacity and functional traffic capacity, introduced by the highway capacity manual (HCM) as a conventional method for estimating functional capacity. Thus, maximum allowed pollution is considered a constraint on a vehicle flow rate, which shows the proper traffic flow for selected streets in Tehran, Iran's capital. The paper concludes that traffic capacity under noise and air pollution constraints is much less (approximately one-fourth and one-eighth for noise and air pollution respectively) than the current highway capacity estimated using HCM guidelines. Therefore, to save the cities like Tehran from noise and air pollution, traffic flows should be limited to the level of environmental capacity by implementing some travel demand management (TDM) policies like road pricing.
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المؤلفون: Hesham Eldeeb, Essam Radwan, Hatem Abou-Senna
المصدر: Journal of Traffic and Transportation Engineering (English ed. Online), Vol 8, Iss 5, Pp 735-750 (2021)
مصطلحات موضوعية: Decision support system, Computer science, Controller (computing), Real-time computing, 0211 other engineering and technologies, Transportation, 02 engineering and technology, Traffic engineering, 021105 building & construction, 0502 economics and business, Headway, Peer-to-peer logic, Civil and Structural Engineering, 050210 logistics & transportation, TA1001-1280, 05 social sciences, Detector, Flashing, Flashing yellow arrow, Transportation engineering, Data extraction, Four section head, State (computer science), Permissive left-turn, Communication channel
الوصف: The flashing yellow arrow (FYA) signal display creates an opportunity to enhance the left-turn phase with a variable mode that can be changed on demand. This research develops an integrated general purpose data collection module that time stamps detector and phase state changes within a National Electrical Manufacturers Association (NEMA) actuated traffic signal controller to provide recommendations for the flashing yellow arrow left-turn mode on a cycle-by-cycle basis. 115 left-turn approaches at 38 intersections with locations across the State of Florida were analyzed totaling 1370 h of video data processed including off-peak and peak conditions. Video data extraction was an essential step in developing the gap thresholds for the permissive left-turn. Actual intersection field data were obtained through loop detector mapping to the controller in the lab in real-time mode using a peer-to-peer logic environment. A custom communications software was developed to retrieve instantaneous channel input data, synchronize opposing through green phase, analyze traffic information, provide the algorithm decision, and generate a real-time log recording the events to determine whether it would be optimal to switch the red arrow to a flashing yellow arrow. The algorithm determines the time interval between the successive arrivals of vehicles and computes the corresponding headway for each lane by cycle on a second-by-second basis. Peer-to-peer logic is a necessary step to verify and validate new traffic concepts prior to field-testing and offers the advantage of acquiring and analyzing real-time traffic data coupled with video feed with the benefit of a safe environment.
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