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  • Mobility and traffic research  (18)
  • 1
    Online Resource
    Online Resource
    SAGE Publications ; 2019
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2673, No. 11 ( 2019-11), p. 296-308
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2673, No. 11 ( 2019-11), p. 296-308
    Abstract: It is of interest to federal and state agencies to develop an advanced uniform method for estimation of vehicle miles traveled (VMT) on local roads which can be used as a guideline for agencies nationwide. The purpose of this study is to propose advanced innovative approaches for estimating VMT on local roads and analyze the feasibility of applying these methods. The paper presents a methodology and procedure for estimating local road VMT using GPS vehicle trajectory data and an all-street road network and expands these methodologies and results to determine the minimum required GPS sample size. The Federal Highway Administration and other transportation agencies may consider using these methodologies as a future guide to update VMT estimates with minimal additional cost requirements. The key finding of the research is that it is feasible to use new GPS vehicle trajectory data to estimate VMT on non-Federal Aid System roadways. The sample size of this data allows the application of this new method across the nation. The accuracy of this method was tested for the State of Maryland. Once such statewide GPS data is obtained by a given state, the methodology can be easily applied to that state as well.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
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  • 2
    Online Resource
    Online Resource
    SAGE Publications ; 2023
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2677, No. 3 ( 2023-03), p. 1340-1356
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2677, No. 3 ( 2023-03), p. 1340-1356
    Abstract: Dynamic traffic assignment (DTA) methods have been developed fruitfully in theory but are limited in application. Reasons may include the high computational complexity, the difficulty in model calibration, and the reliance on accurate and complete origin–destination (OD) data. Recognizing the incompleteness of OD data in the real world, this paper proposes a deep learning-based DTA model. Specifically, a convolution neural network (CNN) is chosen to account for the spatial correlation of OD pairs. The CNN-based DTA model is trained with the input of historical OD data (incomplete because of limited survey tools) and the output of link flow data (complete thanks to detection technologies). These data are obtained first by simulations in experimental networks and then from an empirical survey in Dazhou, China. Extensive experiments are done about various levels of data incompleteness (measured by the percentage of missing OD data). Comparisons show that the trained CNN-based DTA model performs better with higher accuracy than other common statistical/machine learning algorithms (e.g., feed-forward neural network, k-nearest neighbor, and Kriging). The proposed model also shows robustness to the small-sized dataset, data noise, and network changes. Additional examinations include employing the proposed framework to learn and estimate traffic flow characteristics (i.e., average speed and travel time) and the dynamic flow of turning movements at intersections. Lastly, a case study demonstrates the application of the proposed model using real data. Overall, this study indicates the promising prospect of the CNN-based DTA model as a supplement to traditional ones.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
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  • 3
    Online Resource
    Online Resource
    SAGE Publications ; 2019
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2673, No. 11 ( 2019-11), p. 791-800
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2673, No. 11 ( 2019-11), p. 791-800
    Abstract: Because of limited access to global positioning system (GPS) signals, accurate and reliable localization for intelligent vehicles in underground parking lots is still an open problem. This paper proposes a multi-view and multi-scale localization method aiming at solving this problem. The proposed method is divided into an offline mapping stage and an online localization stage. In the mapping stage, the offline map is generated by fusing 3-D information, WiFi features, visual features, and trajectory from visual odometry (VO). In the localization stage, WiFi fingerprint matching is exploited for coarse localization. Based on the result of coarse localization, multi-view localization is exploited for image-level localization. Finally, metric localization is exploited to refine the localization results. By applying this multi-scale strategy, it is possible to fuse WiFi localization and visual localization and reduce the image matching and error rate to a great extent. Because of exploiting more information, multi-view localization is more robust and accurate than single-view localization. The method is tested in a 2,000 m 2 underground parking lot. The result demonstrates that this method can achieve sub-meter localization on average. The proposed localization method can be a supplement to the existing intelligent vehicle localization techniques.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 2403378-9
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  • 4
    Online Resource
    Online Resource
    SAGE Publications ; 2009
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2124, No. 1 ( 2009-01), p. 222-230
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2124, No. 1 ( 2009-01), p. 222-230
    Abstract: The distribution of time headway has long been a research topic because headway between vehicles is an important flow characteristic affecting safety, level of service, driver behavior, and capacity of a transportation system. However, almost all reported research on headway is focused on mixed vehicular flow without considering the difference in headway with respect to different vehicle types. In this paper, with the use of 1-day freeway traffic data from Interstate 35 in Austin, Texas, four time headway types based on different combinations of leading vehicles and following vehicles–-car–truck, truck–car, truck–truck, and car–car–-are analyzed at different traffic flow levels. Statistical comparisons between each vehicle type–specific headway and mixed vehicle–type headway are made to verify their significant differences. The paper demonstrates the necessity of vehicle type–specific headway study. The results of the paper not only identify qualitative differences between the vehicle type–specific headways and distributions, but also can be used as a reference for practical applications, especially for improving microscopic traffic simulation models.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2009
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  • 5
    Online Resource
    Online Resource
    SAGE Publications ; 2016
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2580, No. 1 ( 2016-01), p. 34-46
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2580, No. 1 ( 2016-01), p. 34-46
    Abstract: This study evaluated the benefits of geogrid reinforcement on unbound granular materials (UGMs) in terms of cross-anisotropy and stress-dependent permanent deformation by using repeated-load triaxial (RLT) tests. One type of crushed granite material and three types of geogrid were selected for the RLT tests. The influence of the aperture type, the sheet stiffness, and the location of the geogrid was quantified in terms of the increase of resilient modulus and the reduction of permanent deformation of the UGMs. The RLT test results indicated that the geogrid reinforced both the vertical and horizontal resilient moduli of the UGM but did not affect its anisotropic ratio. The geogrid with triangular apertures and high sheet stiffness placed in the middle of a UGM specimen provided the most benefits in reinforcing the cross-anisotropic resilient modulus and reducing the permanent deformation. To characterize the stress-dependent permanent deformation of geogrid-reinforced UGMs, a mechanistic–empirical rutting model was proposed by incorporating a softening stress term and a hardening stress term into the Tseng–Lytton model. A new permanent deformation test protocol was developed to determine the model coefficients and to examine the model’s prediction accuracy. The comparison of the model-predicted permanent strain curves with those measured in laboratory tests confirmed that the developed rutting model accurately captured the stress dependences of the permanent deformation for the geogrid-reinforced UGM. The determined rutting model coefficients can be used to predict the permanent deformation of UGMs at any stress level and number of load repetitions.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
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  • 6
    Online Resource
    Online Resource
    SAGE Publications ; 2015
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2504, No. 1 ( 2015-01), p. 159-167
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2504, No. 1 ( 2015-01), p. 159-167
    Abstract: The monitoring of bridge structures during construction has received significant attention in recent years as accelerated construction techniques are being used more frequently. Continuous monitoring systems can verify that quality and safety are maintained during construction by minimizing construction uncertainties and aiding designers to compare the actual behavior of a structure with the design models. Additionally, the behavior of structures in different stages of construction may be important in the definition of abnormal responses (e.g., the loss or reverse of a previously measured dead load) during the life span of a bridge. This paper gives an overview of the monitoring system for substructure construction that was considered for the Ironton–Russell Bridge between Ironton, Ohio, and Russell, Kentucky, during its design and service stages. First, the sensory network of the bridge will be detailed. Second, data processing (which involves two anomaly detection algorithms) and other components of the monitoring system will be presented. Finally, some of the data collected by the monitoring system during construction will be analyzed, and a comparison between the theoretical and actual response to a major vertical posttensioning event will be made. The result showed that the actual response matched the expected response and that the newly developed algorithm has a promising potential for tracking daily thermal responses.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2015
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  • 7
    Online Resource
    Online Resource
    SAGE Publications ; 2018
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2672, No. 50 ( 2018-12), p. 23-34
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2672, No. 50 ( 2018-12), p. 23-34
    Abstract: The passenger transportation hub plays a crucial role in the urban transportation system. Analyzing transportation hub related travel demand is necessary to support urban transportation planning and management. However, it is difficult to use the traditional travel survey methods to study travel demand because tracking passenger travel trajectories is a near impossible task. The location information from the cellular system provides a feasible way to solve the problem. This paper concentrates on applying mobile phone data to study passenger travel demand related to the Hongqiao transportation hub in Shanghai, China. First, a method is introduced to collect passenger travel information related to the hub from mobile phone data. Then, travel demand indexes are presented to characterize the travel demand in a visual way. Finally, transportation corridors, which connect the hub and other urban areas, are identified to analyze the distribution of travel demand more thoroughly. The results illustrate that the passenger travel demand shows an obvious tide pattern in the city area with the Hongqiao transportation hub as the center. Moreover, there are two identified transportation corridors which reveal the major distribution directions of the passengers, that is, the city center and the Zizhu industrial development zone. The approach in this study testifies that mobile phone data has great potential for transportation planning and management related to transportation hubs.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
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  • 8
    Online Resource
    Online Resource
    SAGE Publications ; 2014
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2433, No. 1 ( 2014-01), p. 121-128
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2433, No. 1 ( 2014-01), p. 121-128
    Abstract: Narrow, rural two-lane highways are mostly characterized by low design features, light traffic volumes with high crash rates, and particularly high fatal crash rates. About 5,000 mi of these highways are administered by the Louisiana Department of Transportation and Development. Run-off-roadway (ROR) crashes are the most common type of crashes on narrow, rural two-lane highways. Because the Manual on Uniform Traffic Control Devices does not require edgelines, edgelines are not found on many such highways because of their low traffic volumes. There are two main concerns for edgeline implementation on narrow two-lane highways: the potential increase in head-on collisions and the added maintenance cost to the already constrained annual maintenance budget. The second part of a study that evaluated the safety impact of edgelines on narrow, rural two-lane highways in Louisiana is presented. On the basis of data collected from 10 locations, the first part of the study proved that edge lines centralized the lateral position of vehicles. This second part of the study evaluated the safety performance before and after the implementation of edgelines on roadway segments selected from all Louisiana districts. By using the empirical Bayes method, the study showed that edgeline implementation significantly reduced expected crash frequencies. Edgeline implementation reduced ROR crashes as well as head-on crashes. The implementation of edgelines benefited primarily male drivers and young drivers. Because of the crash-decreasing trend observed in the 3-year period classified as the after period in this study, the final estimated crash modification factor was 0.85 with a standard deviation of 0.039. The high benefit–cost ratio strongly supports edgeline implementation on narrow, rural two-lane highways in Louisiana.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
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  • 9
    Online Resource
    Online Resource
    SAGE Publications ; 2016
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2555, No. 1 ( 2016-01), p. 65-71
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2555, No. 1 ( 2016-01), p. 65-71
    Abstract: Pavement preservation projects typically require construction workers to conduct their work in close proximity to ongoing traffic. During paving operations, workers are located within a protected work zone. Some are situated nearby or engaged with the equipment, while others may be a long distance from the equipment and on foot. The study reported here was conducted to investigate how temporary advisory speed signs located periodically in a work zone affected vehicle speeds within highway paving project work zones. The study used an experimental approach that involved a multilane paving project on a high-speed roadway in Oregon. The posted regulatory speed on the roadway was 65 mph, which was reduced temporarily to 50 mph in the work zone. During construction, 35 mph advisory signs were posted along with other traffic control devices (e.g., “Speed 50” signs with radar speed display and portable changeable message signs on rollers), and the impact they had on vehicle speed and speed variability was evaluated. The research findings indicated that use of the 35 mph signs led to lower vehicle speeds within the work zone. The reduction in speed was greater by passenger cars than by trucks. The use of 35 mph advisory signs in work zones is recommended to help reduce vehicle speeds through the entire work zone and to minimize safety risks, especially to workers on foot and situated away from major equipment.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
    detail.hit.zdb_id: 2403378-9
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  • 10
    Online Resource
    Online Resource
    SAGE Publications ; 2014
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2430, No. 1 ( 2014-01), p. 72-82
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2430, No. 1 ( 2014-01), p. 72-82
    Abstract: Trip distribution is an invaluable portion of the transportation planning process; this distribution leads to the creation of origin–destination (O-D) matrices. Location-based social networking (LBSN) has increased in popularity and sophistication and has emerged as a new travel demand data source. Users of LBSN provide location-sensitive data interactively with mobile devices, including smartphones and tablets. These data can provide O-D estimates with significantly higher temporal resolution at a much lower cost in comparison with traditional methods. An LBSN O-D estimation model based on the doubly constrained gravity model was proposed to improve a previously proposed model based on the singly constrained gravity model. The proposed methodology was calibrated and comparatively evaluated against the O-D matrix generated by the method based on the singly constrained gravity model as well as a reference matrix from the local metropolitan planning organization. The results of this method illustrate significant improvement in reducing the O-D estimation errors caused by the sampling bias from the method based on the singly constrained gravity model.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
    detail.hit.zdb_id: 2403378-9
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