18,349 research outputs found
A Framework for Developing and Integrating Effective Routing Strategies Within the Emergency Management Decision-Support System, Research Report 11-12
This report describes the modeling, calibration, and validation of a VISSIM traffic-flow simulation of the San José, California, downtown network and examines various evacuation scenarios and first-responder routings to assess strategies that would be effective in the event of a no-notice disaster. The modeled network required a large amount of data on network geometry, signal timings, signal coordination schemes, and turning-movement volumes. Turning-movement counts at intersections were used to validate the network with the empirical formula-based measure known as the GEH statistic. Once the base network was tested and validated, various scenarios were modeled to estimate evacuation and emergency vehicle arrival times. Based on these scenarios, a variety of emergency plans for San José’s downtown traffic circulation were tested and validated. The model could be used to evaluate scenarios in other communities by entering their community-specific data
The COST IRACON Geometry-based Stochastic Channel Model for Vehicle-to-Vehicle Communication in Intersections
Vehicle-to-vehicle (V2V) wireless communications can improve traffic safety
at road intersections and enable congestion avoidance. However, detailed
knowledge about the wireless propagation channel is needed for the development
and realistic assessment of V2V communication systems. We present a novel
geometry-based stochastic MIMO channel model with support for frequencies in
the band of 5.2-6.2 GHz. The model is based on extensive high-resolution
measurements at different road intersections in the city of Berlin, Germany. We
extend existing models, by including the effects of various obstructions,
higher order interactions, and by introducing an angular gain function for the
scatterers. Scatterer locations have been identified and mapped to measured
multi-path trajectories using a measurement-based ray tracing method and a
subsequent RANSAC algorithm. The developed model is parameterized, and using
the measured propagation paths that have been mapped to scatterer locations,
model parameters are estimated. The time variant power fading of individual
multi-path components is found to be best modeled by a Gamma process with an
exponential autocorrelation. The path coherence distance is estimated to be in
the range of 0-2 m. The model is also validated against measurement data,
showing that the developed model accurately captures the behavior of the
measured channel gain, Doppler spread, and delay spread. This is also the case
for intersections that have not been used when estimating model parameters.Comment: Submitted to IEEE Transactions on Vehicular Technolog
Traffic simulation in 3D world
This paper is the result of more than three months of research completed at the School of the Built Environment, Virtual Environment Suite. This study focusing on measuring the impacts of a change in the infrastructure using a 3D traffic simulation model. Various aspects about the research area and the simulation model were explained. Details on technical aspects of the simulation and the modelling are also given. The focus will lay on motor traffic and thus especially on the changes in traffic circulation as a result of relocating the car access of the City Site. The impacts of the infrastructure changes will be analysed, by simulating the current situation as well as the future situation. Comparison of the different simulations will show the impacts
VANET Connectivity Analysis
Vehicular Ad Hoc Networks (VANETs) are a peculiar subclass of mobile ad hoc
networks that raise a number of technical challenges, notably from the point of
view of their mobility models. In this paper, we provide a thorough analysis of
the connectivity of such networks by leveraging on well-known results of
percolation theory. By means of simulations, we study the influence of a number
of parameters, including vehicle density, proportion of equipped vehicles, and
radio communication range. We also study the influence of traffic lights and
roadside units. Our results provide insights on the behavior of connectivity.
We believe this paper to be a valuable framework to assess the feasibility and
performance of future applications relying on vehicular connectivity in urban
scenarios
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