• Vol 6, No 5 (2015)
  • Civil Engineering

Median-type Adjustment Factor for Road Capacity Calculation

Martha Leni Siregar, Heddy R Agah, Fadhliya Afifa Arifin

Corresponding email: leni@eng.ui.ac.id


Published at : 30 Dec 2015
IJtech : IJtech Vol 6, No 5 (2015)
DOI : https://doi.org/10.14716/ijtech.v6i5.1358

Cite this article as:

Siregar, M.L., Agah, H.R., Arifin, F.A., 2015. Median-type Adjustment Factor for Road Capacity Calculation. International Journal of Technology. Volume 6(5), pp. 762-769

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Martha Leni Siregar Department of Civil Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI Depok, Depok 16424, Indonesia
Heddy R Agah Department of Civil Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI Depok, Depok 16424, Indonesia
Fadhliya Afifa Arifin Department of Civil Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI Depok, Depok 16424, Indonesia
Email to Corresponding Author

Abstract
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A median is required for a two-way road to separate the opposite traffic and prevent head-on collisions. In road capacity calculation, the median factor contributes in terms of its existence regardless of the difference in median types. Road capacity is determined by a number of geometric factors such as road types, width of carriageway, shoulder/curb characteristics, and the presence/absence of medians, etc. The contributions of these factors are represented by the coefficients in the capacity calculations. Despite the different types of medians, the Indonesian Highway Capacity Manual (IHCM) does not adopt different coefficients to accommodate the effects in the capacity. The aim of this study is to obtain an adjustment factor for road capacity calculation based on median types. The method of this study adopts video recordings of real traffic moving along three different types of medians: raised medians, fenced medians, and line medians. As it is assumed that the effects of different median types are expressed in the vehicles’ safety distances from medians, the capacity of the road will also vary by types of medians. The adjustment coefficients for roads with raised medians, fenced medians, and line medians obtained are: 0.79, 0.78, and 0.81, respectively. The results of this study confirm that in addition to the presence of the medians, the types should essentially be considered in calculating the road capacity. The result of this study will contribute to the enrichment of the road capacity calculation in the IHCM.

Drivers’ hazard perception, Median, Median-type adjustment factor, Road capacity, Vehicle-to-median distance

References

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