【正文】 gn concept of “the cost of full lifecycle”,that’s to say, the road lines should be interpared in such stages as construction, maintenance, operation and management,and both the construction cost and operating cost should be taken into account. In addition,we need to carry out the economic analysis in the feasibility study for the road’s construction,and to carry out the analysis in terms of economy and social benefits when paring the schemes of parts of the road, so that the linebit and its technical indicators could be settled down by its service level and the benefits for economy and society. . The protection for water resources At present, our country’s intensity of controlling water pollution is increasing year after year, and people have realized that the seriousness of ecological deterioration caused by water pollution. So when reservoirs, lakes and other water bodies get involved in the process of line selection, we should pay special attention to whether these water bodies are the residents’drinking water sources or not. Because the water on the pavement will cause contamination, direct discharging the above water bodies will damage the water resources and threat the lives of urban residents. Therefore,when setting down the lines,we must give priority to protecting the water resources,set them down at the lower reaches of water bodies or beside the protection line of water some special circumstances such as having to build a bridge over the water or set down the line at the upper reaches,we should carry out especial drainage design, make the water on pavement be discharged and disposed seperately ,and arrange the preplans for the accidents caused by the hazardous chemicals,in order to ensure the water safety.. The protection for cultural relics If there is a cultural relic in the area going to be used for road constrution or within the demolition site,we have to evaluate the level of the cultural relic according to Law of the People39。一般設(shè)計者的習(xí)慣思維是“逢山開路，遇水架橋”，這就造成基建工程完成后，大片的植被和原生地貌需要很長時間才能恢復(fù)或根本無法恢復(fù)，甚至造成一系列的環(huán)境災(zāi)害。結(jié)論看似簡單的線位比選其實蘊藏著很大的學(xué)問。交通部組織編寫的《新理念公路設(shè)計指南（2005版）》中明確提出要樹立“全壽命周期成本”的設(shè)計理念，也就是道路線位選擇應(yīng)從建設(shè)、養(yǎng)護、運營、管理等各階段進行全面經(jīng)濟比較，建設(shè)成本和運營成本統(tǒng)籌考慮。線位比選是指在日常設(shè)計工作中，綜合考慮經(jīng)濟、文化、環(huán)境、行人、安全、道路交叉等各方面因素，結(jié)合現(xiàn)場實際情況，在不影響當(dāng)?shù)厝罕娚?、?jīng)濟發(fā)展的前提下，多線位比選、多方面比較，得出一個最經(jīng)濟、最可行、最合理同時滿足國家相關(guān)規(guī)范、政策的線位。 on the basis of environment。s Republic of China on the Protection of Cultural Relics, decide whether adjust the linebit or not ,because the cultrual relics can not b