Evaluation Indices System of Freeway Alignment Design and Natural Environment Protection

Highway construction inevitably may cause certain influence to the natural environment along the route, particularly in design stage; if the route selection is unreasonable, it will certainly poses the serious threat to the natural environment. On the contrary, good design can reasonably develop, use, protect and promote the value of natural environment along the route. In order to assess different route design schemes, firstly, it should establish a reasonable index system based on the aim of alignment design, then, select impersonal assessment method. According to the aim of alignment design of freeway on mountain areas, eleven indexes have been selected by design investigation, experts consultation and combining criterion indexes, such as the flexibility of route adapting to terrain, the maximum height of fill slope, the maximum depth of digging slope and so on. The grade criterion of indexes has also been studied. Application results shows that the index system is representative, exercisable and simple for selecting good design which can reduce freeway´s impact on natural environment along the route.