Geometric design consideration in rehabilitation of urban arterial roads (case study B084, Horana - Colombo Road)

Abstract

Geometric improvement plays a significant part in urban arterial road rehabilitation by addressing social, environmental, and economic issues. The study selected the Horana - Colombo (B084) road rehabilitation project as the case study. During the investigation, several issues related to the project scope, duration, and society were identified. In this study, priority weightages were systematically assigned through expert interviews. These weightages were readjusted using the known costs incurred for implementing solutions for several issues. Moreover, these issues were ranked according to the summation of the readjusted weightages. Further, a checklist with priority order was proposed based on the identified issues and the ranking. The results show that drainage design issues are the most critical design consideration. The second most critical design consideration is geometric design at fuel stations. Third most critical issue is the vertical alignment design at areas with underlying rock areas and utility lines. Traffic count should be conducted at the junctions before implementing the geometric design. Access issues are a significant design consideration in the geometric design. Furthermore, coordinating with the authorities for the utility maintenance is necessary to minimise road damage. Following design and construction sequences is necessary for minimizing line drain construction issues. Pavement design optimization saves cost and the time of construction. The existing horizontal and vertical alignment should be harmonised during the geometric design. Incorporating this checklist with priority order in the geometric design of rehabilitation of urban arterial roads will ensure that the road is constructed safely, efficiently, and cost-effectively.