GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Mobility and traffic research  (146)
  • 1
    Online Resource
    Online Resource
    Learning-Based Stochastic Driving Model for Autonomous Vehicle Testing
    SAGE Publications ; 2022
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2676, No. 1 ( 2022-01), p. 54-64
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2676, No. 1 ( 2022-01), p. 54-64
    Abstract: In the simulation-based testing and evaluation of autonomous vehicles (AVs), how background vehicles (BVs) drive directly influences the AV’s driving behavior and further affects the test results. Most existing simulation platforms use either predetermined trajectories or deterministic driving models to model BV behaviors. However, predetermined BV trajectories cannot react to AV maneuvers, and deterministic models are different from real human drivers because of the lack of stochastic components and errors. Both methods lead to unrealistic traffic scenarios. This paper presents a learning-based stochastic driving model that meets the unique needs of AV testing (i.e., interactive and human-like stochasticity). The model is built based on the long short-term memory architecture. By incorporating the concept of quantile regression into the loss function of the model, the stochastic behaviors are reproduced without prior assumption of human drivers. The model is trained with the large-scale naturalistic driving data (NDD) from the Safety Pilot Model Deployment project and compared with a stochastic intelligent driving model (IDM). Analysis of individual trajectories shows that the proposed model can reproduce more similar trajectories of human drivers than IDM. To validate the ability of the proposed model in generating a naturalistic driving environment, traffic simulation experiments are implemented. The results show that traffic flow parameters such as speed, range, and time headway distribution match closely with the NDD, which is of significant importance for AV testing and evaluation.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.1177/03611981211035756
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Unified Route Choice Framework : Specification and Application to Urban Traffic Control
    SAGE Publications ; 2014
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2466, No. 1 ( 2014-01), p. 105-113
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2466, No. 1 ( 2014-01), p. 105-113
    Abstract: The route choice system and the traffic control system (TCS) constitute two major approaches to mitigating congestion in urban road networks. The interaction between signal control and route choice is considered from a narrower route choice system perspective, with the focus on route choice models for operational purposes. The goal is to analyze the relative performance of alternative route choice models as different assumptions are made about the type of TCS in use. To this end, an agent-based framework for formulating different route choice models is defined, and this framework is integrated with a microscopic traffic simulation environment. Within the framework, each agent's memory is updated repeatedly (daily) to reflect available prior individual and social experience, and then a route is chosen by a probabilistic sequential decision-making process. Several previously developed route choice models from the literature are implemented with the framework, and their performance, along with some additional hybrid models that are suggested by the modeling framework, is evaluated on two simulated real-world systems: a 32-intersection road network in Pittsburgh, Pennsylvania, running with a SYNCHRO-generated coordinated timing plan and the same road network running with the scalable urban traffic control (SURTRAC) adaptive TCS. The results show that specific route choice models perform differentially when applied in conventional and adaptive traffic control settings and that better overall network performance for all route choice models is achieved in the adaptive control setting. This unified framework also makes it possible to analyze the performance impact of route choice model components and to formulate better-performing hybrid models.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/2466-12
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Implications of Field Loading Patterns on Different Tie Support Conditions using Discrete Element Modeling: Dynamic Responses
    SAGE Publications ; 2019
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2673, No. 2 ( 2019-02), p. 509-520
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2673, No. 2 ( 2019-02), p. 509-520
    Abstract: With increasing demands for rail passenger and freight operations, sharing a line or track is an economical solution if operational efficiency and track reliability challenges can be accommodated properly. This paper presents findings of ballast layer dynamic responses related to four different freight and passenger car loading patterns studied for four different tie support conditions using the Discrete Element Method (DEM). With the DEM model setup being identical for each support condition, ballast particle contact force networks were visualized first under one dynamic load cycle. Certain load transfer chains were observed associated with all four support conditions. Next, crosstie dynamic velocities were analyzed for all sixteen combinations of the different loading patterns and support conditions. The freight car loads traveling at 50 mph could induce higher crosstie vibration velocities than the lighter passenger car loads traveling at 110 mph and 150 mph in three support conditions: lack of center support, high center binding, and lack of rail seat support. Dynamic movements of ballast particles were visualized in velocity vector plots based on their initial and final centroid coordinates. Results reveal that for the same axle load, higher speeds will cause larger ballast particle movements. However, with higher load magnitudes, larger particle movements can be observed even at lower speeds. Generally, high center binding results in the smallest particle movement while lack of center support presents the largest particle movement. Dynamic load responses of the ballast layer simulations provide insights into evaluating and optimizing tracks to be shared by passenger and freight trains.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.1177/0361198118821936
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Characterizing and Modeling Observed Lane-Changing Behavior: Lane-Vehicle-Based Microscopic Simulation on Urban Street Network
    SAGE Publications ; 2000
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 1710, No. 1 ( 2000-01), p. 104-113
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 1710, No. 1 ( 2000-01), p. 104-113
    Abstract: Key findings are discussed regarding characteristics of lane-changing behavior based on observations of an urban street network. An in-depth exploration of observed lane-changing behavior and its modeling were conducted using vehicle trajectory data extracted from video observations using VEVID, a software package developed by the authors, integrated with a video-capture system. As a result, rules for modeling lane-changing behavior are proposed with respect to various types of lane changes. A lane-changing model consists of three components: a decision model, a condition model, and a maneuver model. Drivers’ decisions to change lanes depend on travel maneuver plans, the current lane type (i.e., the relationship between the current lane and the driver’s planned route), and traffic conditions in the current and adjacent lanes. A lane-changing condition model is the description of acceptable conditions for different types of lane changes. A lane-changing maneuver model describes a vehicle’s speed and duration when a certain type of lane change occurs. All of these models are established in a heuristic structure.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/1710-12
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2000
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Transit Path-Choice Models That Use Revealed Preference and Stated Preference Data
    SAGE Publications ; 2002
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 1799, No. 1 ( 2002-01), p. 58-65
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 1799, No. 1 ( 2002-01), p. 58-65
    Abstract: A study was conducted of the trip-making behavior of transit users in a complex transit network with input of travel information in an increasingly complex and information-rich transit environment. A modeling framework to assess the preferences of commuters toward a range of factors and alternatives was produced. Path-choice models on transit services of Singapore were developed using mixed revealed preference (RP) and stated preference (SP) data. RP models were estimated using data obtained in the 1997 Household Interview Survey. An SP survey based on 44 scenarios was conducted, which yielded 307 responses at 12 different locations in Singapore. Models based on pure RP data, pure SP data, and mixed RP and SP data were estimated. For transit users, the decision of which path to take relies on the trade-offs among attributes of journey time and other factors. The significant attributes in the models indicate that the transit path choice is a multi-criteria decision-making process. This suggests that the usual way of transit path assignment in many planning models based on single criterion, such as minimum time, may not be appropriate in choice situations. Path-choice models developed and calibrated provide important fundamental knowledge of the way transit services are to be utilized by travelers, for use in a wide range of applications, such as multimodal transit service planning models, transit demand modeling, and integration of the transit path-choice models in intelligent transportation systems applications.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/1799-08
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2002
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Robotic Machine for Highway Crack Sealing
    SAGE Publications ; 2003
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 1827, No. 1 ( 2003-01), p. 18-26
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 1827, No. 1 ( 2003-01), p. 18-26
    Abstract: An operator-controlled crack-sealing machine was developed and tested at the Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center at the University of California, Davis. The machine, integrated onto a single truck, provides ease of operation and a simple, automated method of sealing random pavement cracks. The operator provides the machine its tasks and is the decision maker; the machine automatically performs the repetitive and dangerous tasks of mapping pavement cracks, creating seal paths for the robot, and sealing the cracks. The operator communicates with the machine through a simple user interface adjacent to the driver. This operator control approach drastically reduces the machine’s control complexity relative to fully automated crack-sealing machines. To be able to seal cracks within a full lane without intruding into adjacent lanes, a telescoping long-reach robotic arm was developed that can position the sealing head mounted to its end in a large 3.7- x 4-m (12- x 13-ft) workspace, within 0.4 mm (1/64 in.) at a traverse speed up to 1 m/s (3 ft/s). A special sealant applicator that deploys a pressurized reservoir was developed to allow high-speed and automated sealing operations. A 100-Mbps fast Ethernet and 10-Mbps wireless control network allows for distributed real-time motion control, input/output control, and machine vision. A fully object-oriented, multithreaded Internet-based software architecture allows reliable and efficient system integration and provides an interactive and responsive user interface for feature-rich and easy imaging, path planning, and system control.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/1827-03
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2003
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Current Status and Variability of In-Service Truck Tire Pressures in Texas
    SAGE Publications ; 2003
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 1853, No. 1 ( 2003-01), p. 157-164
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 1853, No. 1 ( 2003-01), p. 157-164
    Abstract: Truck tire pressure is closely related to tire-pavement contact pressure and could be an easy index representing the tire-pavement contact pressure level. To characterize in-service truck tire pressures and truck configurations on Texas highways, a truck survey was conducted on major Texas trucking routes. The survey data demonstrate a significant increase in in-service truck tire pressures in the state of Texas. Analysis of the collected tire-pressure data showed that factors such as axle weight, tire temperature, geographic area, highway class, traveled distance, and axle type are related to the in-service tire-pressure values. In a survey study, a factorial experiment design and a stratified sampling design were used. Analysis of variance, analysis of covariance, and t-tests were used for comparisons of truck tire-pressure data. Laboratory experiments and linear regression were used to identify relationships between the parameters of tire pressure and tire temperature. The survey results for in-service truck tire pressures and the comparisons and analyses of factors differentiating truck tire pressures are presented.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/1853-18
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2003
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Analysis of Platoon Impacts on Left-Turn Delay at Unsignalized Intersections
    SAGE Publications ; 2011
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2223, No. 1 ( 2011-01), p. 80-87
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2223, No. 1 ( 2011-01), p. 80-87
    Abstract: This research aimed to develop a methodology for analyzing the platoon impacts on major-street left-turn (MSLT) delay at two-way stop-controlled intersections. The main idea was to use a microscopic simulation tool to simulate different platoon scenarios in opposing through traffic and then to apply regression models to capture the impacts of platoons on the delay of MSLT. Two platoon variables were adopted as a simplification of the complex platoon scenarios to make analysis of the platoon effects on MSLT delay practical. The first two steps were to build simulation models for real-world unsignalized intersections and simulate scenarios with a combination of various factors related to platoons in VISSIM simulation. The models were calibrated with field data before simulation started. The next step was to define, derive, and calibrate two platoon variables for describing the duration and intensity of platoon arrivals in the opposing through traffic. This process effectively simplified the large combination of various factors. Finally, the two platoon variables and their relationship with the change factor of MSLT delay were modeled with regression tools. A relationship between the two variables and the delay change factor was established. The relationship indicated a positive effect by upstream platoons on MSLT delay and made it possible to quantify the impacts. The findings in this research could be used for research on platoon or signal impacts on left-turn treatments.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/2223-10
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2011
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Spatiotemporal Data Warehouse for Vehicle Supervision : Grid Time–Indexed Cube Approach
    SAGE Publications ; 2013
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2399, No. 1 ( 2013-01), p. 54-62
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2399, No. 1 ( 2013-01), p. 54-62
    Abstract: The large amounts of spatiotemporal data generated by vehicle supervision systems cannot be efficiently managed by ordinary databases, mainly because of long query responses. To overcome the limitations of ordinary databases, this paper proposes a new approach, the grid time (GT)–indexed cube, which is a spatial grid–indexed, adaptive grid-based, trajectory-supported warehouse for spatiotemporal data. The GT cube partitions an embedded space–time into a set of size-fixed grids to form a cube that continues to grow throughout a constant time interval. Each grid is assigned an identifier composed of its coordinates and start time, and an aggregated value for each grid is stored in the grid records, regardless of the temporal length of the queries. Additionally, the basic grid structure of the GT cube remains unchanged at each time interval. Instead, this method refines the grid in a selected region to handle data skewing by adaptively partitioning the grid into subgrids. After extensive performance studies were conducted with spatiotemporal data from the main vehicle supervision system of Guangdong Province, China, it was observed that the GT cube achieved higher query performance than ordinary data storage technologies under various operational conditions, was easily applicable in practice, and demonstrated compatibility with traditional databases.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/2399-06
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2013
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Susceptibility to Driver Distraction Questionnaire : Development and Relation to Relevant Self-Reported Measures
    SAGE Publications ; 2014
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2434, No. 1 ( 2014-01), p. 26-34
    Details
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2434, No. 1 ( 2014-01), p. 26-34
    Abstract: Driver distraction significantly impairs performance and increases the likelihood of vehicle crashes. Understanding the underlying reasons for distraction engagement as well as individuals’ susceptibility to various types of distractions is a necessary step in developing effective solutions for mitigating distraction. This paper describes the development and initial evaluation of a questionnaire, the Susceptibility to Driver Distraction Questionnaire (SDDQ), which investigates distraction involvement by making a distinction between voluntary and involuntary engagement in secondary activities, or distractions, as referred to in this paper. The paper presents the theoretical underpinnings, the questionnaire itself, as well as the results of an online survey that examined the reliability and validity of the newly developed questionnaire. The analyses show moderate to high levels of internal consistency among the questionnaire items; this consistency provides support to the reliability of the SDDQ. The results also suggest that self-reported engagement in driver distraction is correlated with other self-reported, unsafe driving behaviors. As expected, personality is associated with attitudes and beliefs that motivate voluntary engagement in distraction, while susceptibility to involuntary distraction is related to cognitive limitations. These results indicate that the SDDQ can potentially be a useful tool to study driver distraction and the underlying reasons for distraction engagement.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    URL: Article
    DOI: 10.3141/2434-04
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
    detail.hit.zdb_id: 2403378-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...