Browsing by Author "Delpiano, Rafael"

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    33
    (33, 33) Delpiano, Rafael; 33
    There is growing interest in understanding the lateral dimension of traffic. This trend has been motivated by the detection of phenomena unexplained by traditional models and the emergence of new technologies. Previous attempts to address this dimension have focused on lane-changing and non-lane-based traffic. The literature on vehicles keeping their lanes has generally been limited to simple statistics on vehicle position while models assume vehicles stay perfectly centered. Previously the author developed a two-dimensional traffic model aiming to capture such behavior qualitatively. Still pending is a deeper, more accurate comprehension and modeling of the relationships between variables in both axes. The present paper is based on the Next Generation SIMulation (NGSIM) datasets. It was found that lateral position is highly dependent on the longitudinal position, a phenomenon consistent with data capture from multiple cameras. A methodology is proposed to alleviate this problem. It was also discovered that the standard deviation of lateral velocity grows with longitudinal velocity and that the average lateral position varies with longitudinal velocity by up to 8 cm, possibly reflecting greater caution in overtaking. Random walk models were proposed and calibrated to reproduce some of the characteristics measured. It was determined that drivers’ response is much more sensitive to the lateral velocity than to position. These results provide a basis for further advances in understanding the lateral dimension. It is hoped that such comprehension will facilitate the design of autonomous vehicle algorithms that are friendlier to both passengers and the occupants of surrounding vehicles.
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    33
    (33, 33) Barrera-Medina, Roberto; Delpiano, Rafael; 33
    The genus Chalybion, consisting of potter wasps belonging to the family Sphecidae, exhibits a cosmopolitan distribution. This genus tends to utilize pre-existing cavities or reuse the nests of other wasps for nesting, provisioning these nests with small spiders that will serve as food for their larvae. It has been documented that Chalybion californicum (de Saussure, 1867) shows a preference for reusing the nests of Sceliphron caementarium (Drury, 1773), which is also a Nearctic species. Both species have colonized Peru, and until now, only the presence of S. caementarium was known in Chile. This study reports for the first time the presence of C. californicum in Chile and suggests the possibility of its establishment in this region, thereby illustrating the species and describing its distribution in South America. It discusses the possible distribution area in relation to its behavior of reusing mud nests of other species.
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    (33, 33) Espinoza, Joaquín; Delpiano, Rafael; 33
    A practical challenge facing the adoption of self-driving vehicles is the complex influence of the lateral dimension in vehicle traffic. This phenomenon has received little attention in the literature and few quantitative descriptions of interactions between vehicles are available for model validation. This paper proposes an analysis of the kinematic variables describing vehicle interactions on both axes during overtaking maneuvers using linear as well as nonlinear and nonparametric models based on real-world highway data. The principal findings are as follows: (a) a mutual influence between pairs of vehicles, especially at small lateral separation distances; (b) the higher the longitudinal velocity, the greater the lateral distances, no doubt to avoid collisions; and (c) lateral accelerations that tend to narrow lateral distance are associated with longitudinal accelerations that tend to widen it. These results are consistent across the different models applied and also with previous studies.
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    A two-dimensional car-following model for two-dimensional traffic flow problems
    Delpiano, Rafael; Herrera, Juan Carlos; Laval, Jorge; Coeymans, Juan Enrique