Integrated Model For Optimal Highway Vertical Alignment and Climbing Lane Allocation

• Main Authors: Wu, Yuhwa, 伍裕華
• Other Authors: Lee Yusin
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/29177022423863431277

碩士 === 國立成功大學 === 土木工程研究所 === 86 === Vertical alignment design is an important phase in the highway geometric design process. Even with today''s array of sophisticated computer software, determining the vertical alignment of a highway remains an art and relies mostly on the judgement of experienced engineers. The work becomes even more complicated when climbing lanes come into play. Speed of heavy vehicles is a major consideration in highway vertical alignment. Long and/or steep slopes are usually carefully avoided to maintain the speeds of heavy vehicles at a minimum allowed level. At locations where this is hard or costly, lower speeds can be accepted with the deployment of a climbing lane. While climbing lanes relax the limits on steep slopes, and thus potentially reduce earth and construction costs, the additional lane itself consumes land and cost as well. In practice, it is up to the design engineer to evaluate between the choices, and determine how the climbing lane should be deployed. Typically no systematic effort is employed to optimize the design. In this research, we develop a mixed integer programming model that determines optimal highway vertical alignment and climbing lane allocation simultaneously. Application of the model is demonstrated by several numerical examples. The results are promising and appear to be on the right track.