7,556 research outputs found
The optimization of traffic count locations in multi-modal networks
In this paper we will investigate ways to optimize the placement and number of traffic counters used in multi-modal transportation analysis studies for motorized vehicles, bicycles and pedestrians. The goal is to strike a balance between using as few as possible traffic counters for economical efficiency and deploying more counters which could collect more data. By using shortest path algorithms to determine the paths between the centroids of statistical divisions, we derive from origin-destination matrices which traf
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Accommodating user preferences in the optimization of public transport travel
Measuring delays for bicycles at signalized intersections using smartphone GPS tracking data
The article describes an application of global positioning system (GPS) tracking data (floating bike data) for measuring delays for cyclists at signalized intersections. For selected intersections, we used trip data collected by smartphone tracking to calculate the average delay for cyclists by interpolation between GPS locations before and after the intersection. The outcomes were proven to be stable for different strategies in selecting the GPS locations used for calculation, although GPS locations too close to the intersection tended to lead to an underestimation of the delay. Therefore, the sample frequency of the GPS tracking data is an important parameter to ensure that suitable GPS locations are available before and after the intersection. The calculated delays are realistic values, compared to the theoretically expected values, which are often applied because of the lack of observed data. For some of the analyzed intersections, however, the calculated delays lay outside of the expected range, possibly because the statistics assumed a random arrival rate of cyclists. This condition may not be met when, for example, bicycles arrive in platoons because of an upstream intersection. This justifies that GPS-based delays can form a valuable addition to the theoretically expected values
Calibration of choice model parameters in a transport scenario with heterogeneous traffic conditions and income dependency
By raising the issue of data requirements for the purpose of modal development, validation and application, this study proposes an approach to calibrate choice model parameters in heterogeneous traffic condition using minimal empirical data. For this, a real-world scenario of Patna, India is chosen. For the calibration, a Bayesian framework-based calibration technique (CaDyTS: Calibration of Dynamic Traffic Simulations) is used. Commonly available, mode-specific, hourly-classified traffic counts are used to generate full day plans of agents and their initially unknown activity locations. While the proposed approach implements location choice implicitly, the approach can be applied to a variety of other problems. Further, the effect of household income is included in the utility function to incorporate the effect of income in the decision-making process of individual travelers and to filter out inconsistencies in the daily plans, which originate from the survey data
Quality of Information in Mobile Crowdsensing: Survey and Research Challenges
Smartphones have become the most pervasive devices in people's lives, and are
clearly transforming the way we live and perceive technology. Today's
smartphones benefit from almost ubiquitous Internet connectivity and come
equipped with a plethora of inexpensive yet powerful embedded sensors, such as
accelerometer, gyroscope, microphone, and camera. This unique combination has
enabled revolutionary applications based on the mobile crowdsensing paradigm,
such as real-time road traffic monitoring, air and noise pollution, crime
control, and wildlife monitoring, just to name a few. Differently from prior
sensing paradigms, humans are now the primary actors of the sensing process,
since they become fundamental in retrieving reliable and up-to-date information
about the event being monitored. As humans may behave unreliably or
maliciously, assessing and guaranteeing Quality of Information (QoI) becomes
more important than ever. In this paper, we provide a new framework for
defining and enforcing the QoI in mobile crowdsensing, and analyze in depth the
current state-of-the-art on the topic. We also outline novel research
challenges, along with possible directions of future work.Comment: To appear in ACM Transactions on Sensor Networks (TOSN
Redesigning Large-Scale Multimodal Transit Networks with Shared Autonomous Mobility Services
Public transit systems have faced challenges and opportunities from emerging
Shared Autonomous Mobility Services (SAMS). This study addresses a city-scale
multimodal transit network design problem, with shared autonomous vehicles as
both transit feeders and a direct interzonal mode. The framework captures
spatial demand and modal characteristics, considers intermodal transfers and
express services, determines transit infrastructure investment and path flows,
and designs transit routes. A system-optimal multimodal transit network is
designed with minimum total door-to-door generalized costs of users and
operators, while satisfying existing transit origin-destination demand within a
pre-set infrastructure budget. Firstly, the geography, demand, and modes in
each clustered zone are characterized with continuous approximation. Afterward,
the decisions of network link investment and multimodal path flows in zonal
connection optimization are formulated as a minimum-cost multi-commodity
network flow (MCNF) problem and solved efficiently with a mixed-integer linear
programming (MILP) solver. Subsequently, the route generation problem is solved
by expanding the MCNF formulation to minimize intramodal transfers. To
demonstrate the framework efficiency, this study uses transit demand from the
Chicago metropolitan area to redesign a multimodal transit network. The
computational results present savings in travelers' journey time and operators'
costs, demonstrating the potential benefits of collaboration between multimodal
transit systems and SAMS.Comment: 44 pages, 15 figures, under review for the 25th International
Symposium on Transportation and Traffic Theory (ISTTT25
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