Road intersections are dangerous places in the road system due to the high number of conflicting points between motorized and non-motorized vehicles. In the case of defined traffic volume, several research groups have proven that roundabouts reduce the number of injuries and fatal accident cases. During the last years, many countries have adopted roundabouts as a standard design solution for both urban and rural roads. In the last years, several studies have investigated the performance of roundabouts, among which, include different models with the ability to calculate the entering flow (Qe) as a function of the circulating flow (Qc). Most of existing models have been constructed by using linear or exponential statistical regression. The interpolative techniques found in Classical Statistics are based upon the use of canonical forms (linear or polynomial) that completely ignore the correlation law between collected data. As such, the determined interpolation stems from the assumption that the data represent a random sample. For this research purposes a geostatistical approach has been considered: the relationship Qe vs. Qc has been supposed to be a regionalized phenomenon (1). According to that collected data do not represent a random sample of values but they are supposed to be related to each other with a defined law. This law recognition allows the realization of interpolation based on the real law of the phenomenon (2). In this paper, the fundamental theories, the applied operating procedures and the first results obtained in the modellization of Qe vs. Qc relationship with the application of Geostatistics, are discussed.
A kriging-based technique for studying roundabout performances
MAZZELLA, ALESSANDRO;PIRAS, CLAUDIA;PINNA, FRANCESCO
2011-01-01
Abstract
Road intersections are dangerous places in the road system due to the high number of conflicting points between motorized and non-motorized vehicles. In the case of defined traffic volume, several research groups have proven that roundabouts reduce the number of injuries and fatal accident cases. During the last years, many countries have adopted roundabouts as a standard design solution for both urban and rural roads. In the last years, several studies have investigated the performance of roundabouts, among which, include different models with the ability to calculate the entering flow (Qe) as a function of the circulating flow (Qc). Most of existing models have been constructed by using linear or exponential statistical regression. The interpolative techniques found in Classical Statistics are based upon the use of canonical forms (linear or polynomial) that completely ignore the correlation law between collected data. As such, the determined interpolation stems from the assumption that the data represent a random sample. For this research purposes a geostatistical approach has been considered: the relationship Qe vs. Qc has been supposed to be a regionalized phenomenon (1). According to that collected data do not represent a random sample of values but they are supposed to be related to each other with a defined law. This law recognition allows the realization of interpolation based on the real law of the phenomenon (2). In this paper, the fundamental theories, the applied operating procedures and the first results obtained in the modellization of Qe vs. Qc relationship with the application of Geostatistics, are discussed.
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