版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請進行舉報或認領(lǐng)
文檔簡介
1、附錄 A 外文翻譯A.1 原文CONSISTENCY IN DESIGN FOR LOW-VOLUMERURAL ROADS3By Clarkson H. Oglesby, H. M. ASCE (Reviewed by the Highway Division)ABSTRACT: The 2,000,000 miles of low-volume rural roads in the United States are diffe
2、rent than the high-volume roads and should be designed differently. Traffic volumes on them are low, averaging about 110 vehicles/day or about one vehicle entering a given mile from both ends every three minutes during p
3、eak hours. This contrasts with one vehicle every four seconds at capacity. Geometries on many of these roads have not changed since they were built in the 1920s and 1930s. Today, road improvements should be based on des
4、igns that are consistent and safe, but economical, because needs are great and funds are scarce. Present-day design practices for high volume roads require that each of their features meet a stipulated design speed set
5、 by modern surfaces and vehicles. This practice does not fit the low-volume situation since, whenever possible, drivers will exceed any affordable design speed. They must be slowed down when situations warrant it. A cons
6、istent approach to design which realizes cheap but safe improvements to low-volume roads is proposed. It involves integrating geometric design and positive guidance approaches. Positive guidance employs striping, signi
7、ng, and other devices and strategies to mobilize drivers' senses so that they will drive sensibly. Selecting the less costly between geometry and positive guidance techniques will produce safer roads more cheaply.IN
8、TRODUCTIONThere are approximately 3,200,000 mile (5,100,000 km) of rural roads in the United States. A rough estimate places some 2,000,000 (3,000,000km) of these in a low-volume category; this commonly includes those
9、with average daily traffic less than 400 vehicles/day in both directions. On most of these roads volumes are considerably lower. One estimate places this average at 110 vehicles/day or a possible 20 in the peak hour. Th
10、is means one vehicle every three minutes entering a given mile from both ends. In contrast, a major two-lane road, operating at capacity, will carry possibly 1,800 vehicles/hour so that a vehicle will enter a given mil
11、e every four seconds or 90 times as often.The money available to those responsible for high-volume roads is on the order of ten times as great per mile as for low-volume roads. It follows that strategies for new constr
12、uction, upgrading, or maintenance of low-volume rural roads will be entirely different than for higher-volume roads, if the very limited money available How CONSISTENCY IN PRESENT-DAY GEOMETRIC STANDARDS FOR NEW CONSTRU
13、CTION OR RENOVATION OF LOW VOLUME RURAL ROADSHAS DEVELOPEDAs noted, most of the need for and geometries of low-volume rural roads developed fifty or more years ago to fit specific situations. Unless altered by maintenanc
14、e, betterment, reconstruction, or complete replacement, they have changed little since. At that time, main rural roads were built to meet the same conditions and their geometry was not an issue. For example, as late as
15、 1940, a leading highway engineering text book, by T. R. Agg (1), devotes only 22 pages to the entire subject of geometric design. In it Agg stated that “considerable latitude is allowable in adapting the design to the
16、particular situation (which may be topographical, financial, or political) as long as the design does no violence to basic principles.“ Agg calls for “the exercise of originality and good engineering judgment—that does
17、not necessarily follow stereotyped standards.“It was at about this same time (1937) that AASHO (now AASHTO) created a Committee on Planning and Design Policies. Its aim was to incorporate, in practice, highway design fea
18、tures that would result in maximum safety and utility. From this effort, in the period 1938-1944, came seven policy statements on geometric design that were adopted by AASHO. These were consolidated without change in 19
19、50 into a single volume, Policies on Geometric Highway Design (3). A reworking resulted in a 1954 document called A Policy on Geometric Design (4). This document, commonly called the Blue Book, was redone again and publ
20、ished in 1965 under the same title (5). In 1969, a publication applying more specifically to low-volume rural roads was issued (2). Since that time the appropriateness of these policies, which set standards for all aspe
21、cts of geometric design, have been under almost continuous review and a comprehensive revision is under preparation.From the beginning, those responsible for developing standards for geometric design have been attempting
22、 to keep pace with changes in the characteristics of motor vehicles and the expectations of drivers. This has led to a substantial raising of design controls or features. FACTORS THAT HAVE IMPINGED ON GEOMETRIC STANDARD
23、SFOR LOW-VOLUME RURAL ROADSIn tracing the development of geometric standards and their application over the years in terms of their impact on low-volume rural roads policies, several factors can be seen. These include
24、the following:1. Low-volume road engineers or administrators have made few direct inputs into geometric standards. They have been developed by specialists in geometric design, most of them in the Federal Highway Admini
25、stration. They were adopted after review by geometric-design specialists in the state highway agencies working through AASHTO. Because these agencies deal primarily with high-volume situations, it is claimed that their
26、representatives are not sensitive to the low-volume road situation. For example, the standards for low-volume as well as those for high-volume roads were based on the “design speed“ concept, which has been defined as “
溫馨提示
- 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 眾賞文庫僅提供信息存儲空間,僅對用戶上傳內(nèi)容的表現(xiàn)方式做保護處理,對用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對任何下載內(nèi)容負責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時也不承擔(dān)用戶因使用這些下載資源對自己和他人造成任何形式的傷害或損失。
最新文檔
- 外文翻譯---低流量農(nóng)村公路的統(tǒng)一設(shè)計
- 外文翻譯---低流量農(nóng)村公路的統(tǒng)一設(shè)計
- 外文翻譯---低流量農(nóng)村公路的統(tǒng)一設(shè)計.docx
- 外文翻譯---低流量農(nóng)村公路的統(tǒng)一設(shè)計.docx
- 低流量農(nóng)村公路交通安全特征及保障技術(shù).pdf
- 關(guān)于農(nóng)村公路設(shè)計的思考
- 農(nóng)村公路資料
- 農(nóng)村公路資料
- 農(nóng)村公路專項調(diào)查流程設(shè)計
- 農(nóng)村公路安全設(shè)計研究.pdf
- 農(nóng)村公路提檔升級工程農(nóng)村公路路基施工組織設(shè)計
- 淺談農(nóng)村公路建設(shè)及農(nóng)村公路安保工程設(shè)置
- 農(nóng)村公路的路政管理
- 農(nóng)村公路調(diào)研報告
- 農(nóng)村公路巡查制度
- 象山公路管理段農(nóng)村公路
- 農(nóng)村公路養(yǎng)護辦法
- 農(nóng)村公路巡查制度
- 銅川地區(qū)農(nóng)村公路低造價路面技術(shù)研究.pdf
- 農(nóng)村公路交通安全設(shè)計
評論
0/150
提交評論