Evaluation of 3d Coordination to Maximize Available Stopping Sight Distance in Two-Lane Rural Highways

Autor: Ana Tsui Moreno, Vicente Ferrer, Alfredo Garcia
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: The Baltic Journal of Road and Bridge Engineering, Vol 9, Iss 2, Pp 94-100 (2014)
Druh dokumentu: article
ISSN: 1822-427X
1822-4288
DOI: 10.3846/bjrbe.2014.12
Popis: Sight distance is one of the most important factors of road safety since it allows the driver perceiving, at real time, road characteristics and its surroundings. A misperception of this crucial information could induce a decision to drive with a manoeuvre with less margin of safety. A finite element based software application was developed in Matlab to calculate the sight distance profile at vertical crest curves overlapped with horizontal curves. It was observed that the layout visibility gets principally lost where the superelevation changes its sign; thus, the vertical curve midpoint does not present the highest available sight distance, contrary to the bidimensional analysis. Later, available stopping sight distance was maximized considering different geometric parameters combinations. Stopping sight distance depended mainly on the ratio between the vertical crest curve parameter and horizontal radius, rather than the vertical crest curve parameter. Moreover, values of vertical crest curve parameter lower than the minimal values established in the Spanish design guidelines satisfied the required stopping distance. The offset between horizontal and vertical vertices slightly affects the results; however, the effect of the approach grade is important even if algebraic difference of vertical grades is kept fixed.
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