Transition Curves for Highway Geometric Design

Kobryń, Andrzej

doi:10.1007/978-3-319-53727-6

Cited by 26 publications

(23 citation statements)

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“…For each of them, the chosen variables depend on the geometric model used to define the layout: within the horizontal alignment it is possible to consider, only main axes (Lee et al., ), axes and circular curves (Hirpa et al., ; Mondal et al., ; Jong and Schonfeld, ; Shafahi and Bagherian, ), or axes, circular curves, and transition curves (Casal et al., ; Kang et al., ); within the vertical alignment, vertical curves may be considered (Jong and Schonfeld, ; Shafahi and Bagherian, ), or may not (Hirpa et al., ). In addition, both the horizontal and vertical transition curves can be modeled differently (Bosurgi and D'Andrea, ; Kobryń, ), which also leads to distinct design variables.…”

Section: Introductionmentioning

confidence: 99%

A 3D Model for Optimizing Infrastructure Costs in Road Design

Vázquez-Méndez

Casal

Santamarina

et al. 2018

Computer aided Civil Eng

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In this article, the optimal design of a road joining two terminals is investigated. A geometric model is proposed including horizontal transition curves and vertical curves, obtaining parameterizations for the central axis of the road as well as for its entire surface. These parameterizations allow to express and compute, with great simplicity, the major infrastructure costs, including land acquisition, clearance, pavement, maintenance, and earthwork, where multiple layers of materials with different costs can be handled. The road design problem is formulated as a smooth constrained optimization problem and a two-stage algorithm is suggested for its numerical resolution. Finally, numerical results are presented in an academic test and in a case study that propose designing a bypass in a Spanish national road (N-640) to avoid crossing Monterroso's town center.

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Section: Introductionmentioning

confidence: 99%

A 3D Model for Optimizing Infrastructure Costs in Road Design

Vázquez-Méndez

Casal

Santamarina

et al. 2018

Computer aided Civil Eng

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“…The Bloss curve is a transition curve that reduces the negative effects of geometric discontinuities at the start and end points of the transition curve. The analytical expression of the generic transition curve of length L inserted between a straight line and a circular curve of radius R derives from the equation of a simple 3rd degree polynomial curve (Wladyslaw, 2015), on which four boundary conditions are imposed (Kobryń, 2017): zero curvature and horizontal tangent at the starting point, passing through the midpoint of coordinates (L/2; 0.5R) and passing through the end point of coordinates (L; 1/R). Called 1/r, representing the curvature in correspondence with the generic curvilinear abscissa s, we obtain the Bloss curve equation in implicit form (Bloss, 1936;Taşҫi & Kuloğ, 2011):…”

Section: Bloss Curvementioning

confidence: 99%

The Use of Bloss Curve in The Exit Lanes of Road Intersections

Ciampa

Olita

2020

BJRBE

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The paper proposes the use of the Bloss curve (also known as biparametric or bi-hyperclothoid) as a braking curve in the exit lanes of road intersections. The main international standards continue using the clohoid as the principal transitional geometric element, even though the limits of its use in driving regimes with non-uniform speeds are known. The proposal to use the Bloss curve is aimed at overcoming these limitations and opening a debate on the possible need to codify, even in the international standards, the use of more suitable alternative braking curves. In this context, a kinematic study was conducted by comparing the main parameters of the motion (lateral jerk, lateral acceleration, steering speed) between the Bloss curve and more traditional curves, such as clothoid and Generalized Cornu Spirals (GCS). Nine case studies were conducted, each case was characterized considering the type of transition curve used (clothoid, GCS and Bloss curve) and radius R of the exit curve (R = 60 m, 80 m, 100 m). The numerical values assumed by the kinematic variables along the transition curves were “locally” calculated, i.e. “pointby- point”, to take into account the non-uniform motion regime. The results obtained, limited to the cases studied, show that the Bloss curve better meets the kinematic conditions of the vehicle motion in non-uniform driving regimes. Therefore, the Bloss curve can be considered as a braking curve in the design of road intersections and be a candidate for further investigation to assess any additional benefits in terms of comfort, driving safety and visual perception of the geometric element.

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“…One focus area is the transition curve and the properties this curve should have. Transition curves are used as easement between straight sections and curved section in track and road engineering [1,2]. Over the years different criteria have laid the foundation when deciding the type of curve.…”

Section: -Introductionmentioning

confidence: 99%

Preliminary Studies on Transition Curve Geometry: Reality and Virtual Reality

Brustad

2020

Emerg Sci J

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The topic of transition curves is well known in track and road engineering. Over the years the need for easement between straight and curved sections in railway and road design has grown, with an important reason being increase in vehicle speed. Testing of transitions is often done with graph analysis where the property of lateral change of acceleration is compared between varieties of curves. However, graph analysis does not give a clear understanding of the behaviour of a vehicle in a transition phase the way, for instance, field or laboratory experiments might do. In this paper we present an initial study on the behaviour of a down-scaled vehicle model driving through three distinct transitions from straight to curved sections. In addition we show a comparison of the physical model against a virtual model.

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Transition Curves for Highway Geometric Design

Cited by 26 publications

References 0 publications

A 3D Model for Optimizing Infrastructure Costs in Road Design

A 3D Model for Optimizing Infrastructure Costs in Road Design

The Use of Bloss Curve in The Exit Lanes of Road Intersections

Preliminary Studies on Transition Curve Geometry: Reality and Virtual Reality

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