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1、<p><b>  公路</b></p><p>  20世紀的初期,美國的大多數的街道和馬路都是用泥土、 磚塊和松柏木材建造而成的。由于只是為馬匹、馬車和步行建造的,這些馬路通常得不到細心維護,而且很窄,根本就容納不下汽車的通行。</p><p>  隨著汽車制造業(yè)的發(fā)展,在當地有關部門監(jiān)管下的私立收費公路開始涌現出來。截止到1921年,美國有了共計38.

2、7萬公里的公路。他們中的很多都是采用19世紀蘇格蘭工程師托馬斯?特爾福德和約翰?麥克亞當(碎石路面正是因為他們而得名的)所制定的規(guī)范,他們的標準強調了充分排水的重要性。除此之外,根本就沒有關于大小尺寸、重量限制以及商業(yè)標識的國家標準。在第一次世界大戰(zhàn)期間,全國的馬路幾乎完全被重型卡車破壞了。當艾森豪威爾將軍——在德國服役于美國陸軍第一洲際車隊——于1919年從德國歸國時,他說道:“舊的車隊讓我開始考慮完善的雙車道的公路,但是德國的高速公

3、路讓我看到了更寬闊的跨地域紐帶可顯示出的智慧?!?lt;/p><p>  又經過了一次戰(zhàn)爭,聯邦政府才開始行動起來來建設全國范圍的高速公路體系。第二次世界大戰(zhàn)期間,對貨車和新道路數量的需求大幅度上升。戰(zhàn)爭證明了道路對于防御系統工作的重要性。13%生產防御設備的工廠都是靠卡車來獲得原材料,而且?guī)缀跗渌械墓S半數以上的產品都由機動車來運送。戰(zhàn)爭同樣也暴露了這樣一個現象,對公路的地方管制已經導致已經導致了眾多令人混淆的

4、設計標準。甚至聯邦政府和各州的公路都不遵循基本的標準。一些州允許卡車載重量高達36000磅, 但另一些卻限制載重不可以超過7,000磅。一項政府研究項目建議在全國建設一個總長度為33,920英里的國家公路系統。不久之后,國會很快通過了《1944年聯邦資助公路法案》,這項法案呼吁建立嚴格的、由中央控制的道路設計標準。</p><p>  州際公路系統最終于1956年正式動工,它被譽為上個世紀最偉大的公共工程之一。為

5、了修建長達44000公里的公路、橋梁、隧道網,人們必須制定出數以百計的有針對性的特殊工程設計方案和問題解決方針。方案要考慮到各地的地理特征:山地、 陡坡、 濕地、 河流、 沙漠和平原。道路的各種變量包括地面的陸地的傾斜程度、公路的載重負荷能力、道路的使用強度和地表土壤的種類。城市區(qū)域又是另外一個問題。能夠貫穿或繞過城市區(qū)域的創(chuàng)新設計——其中包括車行道、地下隧道、橋梁、人行天橋以及立交橋等很快地在全國各地涌現出來,并且永遠地改變了美國的面

6、貌。</p><p>  像路易斯安娜的黑爾?博格斯大橋和佛羅里達的陽光高架橋一樣的長跨度混凝土吊索橋,以及像馬里蘭的麥克亨利堡隧道和華盛頓的貝克山的著名隧道,這些跨距長,分段混凝土澆筑的用支索固定的橋梁經受了這個國家很多地理方面的挑戰(zhàn)。由州際公路項目所發(fā)展起來的交通控制系統和建筑方案,很快就影響了全世界的高速公路建設,并在改善城市市區(qū)街道狀況和交通模式方面起到了不可估量的作用。</p><p

7、>  生產方式決定物流模式,現代企業(yè)生產方式經歷從“推”模式向“拉”模式的轉變,促使物流模式也發(fā)生同樣的轉變。過去是以生產推動銷售,物流模式的特點是高庫存;而現代企業(yè)生產方式則是市場需求拉動生產,相應的物流模式也由高效率、低成本的運輸系統和信息系統替代高庫存。在這樣的模式下,運輸出現差錯的后果更嚴重,因此生產企業(yè)選擇運輸方式時除了考慮成本因素,還要考慮貨物價值、運輸速度、能否全程追蹤、以及承運方的服務水平等附加因素,企業(yè)更依賴于使

8、用快捷可靠的運輸方式,在這方面,公路運輸比鐵路運輸更有優(yōu)勢。</p><p>  今天,州際交通體系不僅連接了美國國內的各大主要城市,并且把美國與加拿大和墨西哥連接了起來。出于對安全性的考慮,公路都建有寬敞的車道和路肩、分隔欄或路障、較長的入口和出口車道、為安全拐彎而設計的彎轉,以及限制出入的通道。高速公路上的事故死亡率僅為美國其他道路的一半(高速公路旅客周轉量1億人英里的死亡率是0.86,而其他公路旅客周轉量1

9、億人英里的死亡率則是1.99)。</p><p>  通過打開北美大陸的門,高速公路使在偏遠地區(qū)和農村地區(qū)的人們能夠獲得消費者和服務,并且促進了郊區(qū)城鎮(zhèn)之間的共同發(fā)展,為人們提供了更多的選擇,其中包括工作以及更多地接觸文化節(jié)目、健康護理和其他各項便利服務。但最重要的是,這個州際系統給人們提供了他們最珍惜的東西:個人出行快捷方便。</p><p>  從海上運輸和創(chuàng)造就業(yè)機會的角度來說,州際

10、交通系統一直是國家經濟增長的一個不可或缺的要素:全國75%以上的貨物靠卡車來運輸的,且絕大多數用鐵路以及飛機運輸的貨物最后一段路程還是靠機動車來運輸。公路系統并不僅僅是通過提供運輸線路來影響美國的經濟,它還促使了很多附屬產業(yè)的產生和發(fā)展,比如說服務站、汽車旅館、飯館以及購物中心。它為生產工廠遷至新址以及其他產業(yè)由城區(qū)轉移到鄉(xiāng)村提供了條件。</p><p>  到上世紀末,美國已經建成了集公路、住宅區(qū)街道、高速公路

11、以及免費高速公路于一體的巨大的道路網絡,為數以百萬計的機動車輛提供了便利。洲際公路系統被官方正式更名為艾森豪威爾,以紀念其遠見卓識和領導才華。在開始修建的那一年,艾森豪威爾將軍曾說:“通信系統和交通運輸系統聯合起來的巨大力量正是我們國家最重要的活力來源。沒有了它們,我們僅是各自分裂的松散聯盟?!?lt;/p><p><b>  Highways</b></p><p> 

12、 Early in the 20th century, most of the streets and roads in the U.S. were made of dirt, brick, and cedar wood blocks. Built for horse, carriage, and foot traffic, they were usually poorly cared for and too narrow to acc

13、ommodate automobiles.</p><p>  With the increase in auto production, private turnpike companies under local authorities began to spring up, and by 1921 there were 387,000 miles of paved roads. Many were buil

14、t using specifications of 19th century Scottish engineers Thomas Telford and John Macadam (for whom the macadam surface is named), whose specifications stressed the importance of adequate drainage. Beyond that, there wer

15、e no national standards for size, weight restrictions, or commercial signs. During World War I, roads th</p><p>  It would take another war before the federal government would act on a national highway syste

16、m. During World War II, a tremendous increase in trucks and new roads were required. The war demonstrated how critical highways were to the defense effort: thirteen per cent of defense plants received all their supplies

17、by truck, and almost all other plants shipped more than half of their products by vehicle. The war also revealed that local control of highways had led to a confusing variety of design st</p><p>  The inters

18、tate highway system was finally launched in 1956 and has been hailed as one of the greatest public projects of the century. To build its 44,000 mile web of highways, bridges, and tunnels, hundreds of unique engineering d

19、esigns and solutions had to be worked out. Consider the many geographic features of the country: mountains, steep grades, wetlands, rivers, deserts and plains. Variables included the slope of the land, and the ability of

20、 the pavement to support the load. Innovative desi</p><p>  Long-span, segmented-concrete, cable-stayed bridges such as Hale Boggs in Louisiana and the Sunshine Skyway in Florida, and remarkable tunnels like

21、 Fort MC Henry in Maryland and Mr. Baker in Washington developed under the nation's physical challenges. Traffic control systems and methods of construction developed under the interstate program soon influenced high

22、way construction around the world, and were invaluable in improving the condition of urban streets and traffic patterns.</p><p>  The mode of production determined the logistics mode. The transform of the mo

23、de of production of modern enterprises are changing form the “push” to the” pull”, impelling the logistics mode have the same transform. In the past, the market pushed forward by the manufacture. The feature of the logis

24、tics mode is high inventory, as well as, the mode of production of modern enterprises means that the market demands pull manufacture. The corresponding logistics mode is becoming high inventory, instead </p><p

25、>  Today, the interstate system links every major city in the U.S. and the U.S. with Canada and Mexico. Built with safety in mind the highways have wide lanes and shoulders, dividing medians, or barriers, long entry a

26、nd exit lanes, curves engineered for safe turns, and limited access. The death rate on highways is half that of all other U.S. roads (0.86 deaths per 100 million passenger miles compared to 1.99 deaths per 100 million on

27、 all other roads).</p><p>  By opening the North American continent, highways have enabled consumer goods and services to reach people in remote and rural areas of the country, spurred the growth of suburbs,

28、 and provided people with greater options in terms of jobs, access to cultural programs, health care, and other benefits. Above all, the interstate system provides individuals with what they enrich most: personal freedom

29、 of mobility.</p><p>  The interstate system has been an essential element of the nation's economic growth in terms of shipping and job creation: more than 75 percent of the nation's freight deliveri

30、es arrive by truck. And most products that arrive by rail or air use interstates for the last leg of the journey by vehicle.</p><p>  Not only has the highway system affected the American economy by providin

31、g shipping routes, it has led to the growth of spin-off industries like service stations, motels, restaurants, and shopping centres. It has allowed the relocation of manufacturing plants and other industries from urban a

32、reas to rural.</p><p>  By the end of the century there was an immense network of paved roads, residential streets, expressways, and freeways built to support millions of vehicles, the high way system was of

33、ficially renamed for Eisenhower to honor his vision and leadership. The year construction began he said: "Together, the united forces of our communication and transportation systems are dynamic elements in the very

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