Freeway Environmental Impact Assessment Study Basedon Two-level DEA Model

In our country, built freeway mileage increases year by year. The project construction and put into operation will cause environmental problem which cannot be ignored. Although the environment problem of the construction is short as it can disappear at the end of construction period, the long-term impact of freeway operation cannot be ingored. In order to find the prevention and improvement measures, this paper put forward assess the enironment impact of freeway service life period year by year when the preliminary design stage is end.Wheather the freeway environment impact asseseement index selection is reasonable or not is one of the key of the evaluation. This paper anlyze the environment impact which is caused by the construction projects and combine with the revelent specificiation and existing graduate student achievement. Then sort out the layered evaluation index system. At the same time, considering the freeway construction of environment cost can not be ignored, environmental cost is put forward as a major aspect of the evaluation index. The mainly two aspects of environment cost(environmental protection recovery cost and environmental pollution control cost) calculation formula is put forwad from the point of view of traffic impact of the environmental. For the convenience of the user’s choice flexibility, this paper put forward the freeway environment impact evaluation index which can be divided into must index and optional index.Freeway environmental impact is a complicated system, reasonable choice the comprehensive quantitative evaluation model is another key of the scientific environmental impact assessment. This paper will analyze the freeway environment impact year by year after the preliminary design stage. Because the evaluation index of unit has the same properties. Therefore, this paper choose the DEA model to evaluate through calculating the relative efficiency of each unit. This paper established the environmental impact assessment of indicators and hierarchy system. So Two-level DEA model is proposed for application in freeway environmental impact assessment first time.In order to apply the Two-level DEA model, we treat the evaluation indexes deeply to choose the high impact indicators of evaluation model. Considering the gray correlation between indicators, this article uses the GRA and SE-DEA method combining each other to choose the depth indicators. Then this model is compared with the traditional GRA screening model. GRA and SE-DEA method of combining is more effective.Finally, the chaohui freeway of Guangdong province is as an example to evaluate research. The results show that the proposed within 25 years of sevice life period is more than 75% of the relative efficiency is equal to 1. Then the environmental impact of the freeway in the future years is acceptable.