Abstract:
Selection of urban bypass highway alternatives involves the consideration of competing and conflicting criteria and factors, which
require multicriteria decision analysis. Analytic hierarchy process (AHP) is one of the most commonly used multicriteria decision
making (MCDM) methods that can integrate personal preferences in performing spatial analyses on the physical and nonphysical
parameters. In this paper, the traditional AHP is modified to fuzzy AHP for the determination of the optimal bypass route for
Eldoret town in Kenya. The fuzzy AHP is proposed in order to take care of the vagueness type uncertainty encountered in alternative
bypass location determination. In the implementation, both engineering and environmental factors comprising of physical and
socioeconomic objectives were considered at different levels of decision hierarchy. The results showed that the physical objectives
(elevation, slope, soils, geology, and drainage networks) and socioeconomic objectives (land-use and road networks) contributed
the same weight of 0.5 towards the bypass location prioritization process. At the subcriteria evaluation level, land-use and existing
road networks contributed the highest significance of 47.3% amongst the seven decision factors. Integrated with GIS-based least
cost path (LCP) analysis, the fuzzy AHP results produced the most desirable and optimal route alignment, as compared to the AHP
only prioritization approach.
