道路景觀保護中的變化與環(huán)境

作者：海蒂·霍曼

翻譯：何明一 王亮

校對：王晞月

Text:　Heidi Hohmann

Translator: HE Ming-yi and WANG Liang

Proofreading: WANG Xi-yue

道路景觀保護中的變化與環(huán)境

作者：海蒂·霍曼

翻譯：何明一 王亮

校對：王晞月

Text:Heidi Hohmann

Translator: HE Ming-yi and WANG Liang

Proofreading: WANG Xi-yue

杰克遜、克雷和其他相關(guān)人士對文化景觀的研究及文獻中包含了大量道路景觀的內(nèi)容。然而，交通廊道的保護實際上面臨著許多挑戰(zhàn)，其中大部分來自于他們長且窄的這一特點：雖然道路的結(jié)構(gòu)（路基、路肩、涵洞）相對單一，且管轄權(quán)往往屬于同一機構(gòu)，道路本身維護相對簡單。然而，廊道環(huán)境的保護通常很難，不僅由于它耗資巨大，利益相關(guān)者龐雜，還因其快速的變化。道路景觀是社會環(huán)境下龐大的通訊、交通網(wǎng)的一部分，加之迅猛的技術(shù)變革對其產(chǎn)生的影響，使得道路成為“快速變化”的景觀，即其使用方式、使用感受和自身特征都隨著時間的推移而不斷變化。考慮到如此的變化，長距離交通廊道的保護應(yīng)該如何完成或根據(jù)時間的推移進行調(diào)整？來自美國本土的4個研究案例闡釋了在地方、區(qū)域和國家尺度上道路景觀保護所面臨的挑戰(zhàn)。論述了公園道、風(fēng)景道和高速路的保護方法，及在這種保護方法下資源的動態(tài)轉(zhuǎn)化與演變。

道路；景觀；文脈；公園大道；鄉(xiāng)間小路

1　簡介

20世紀(jì)末涌現(xiàn)出一系列關(guān)于“日?！蔽幕坝^的研究，如J.B. 杰克遜對于文化景觀的思想意識流研究和格雷迪·克雷對路旁“帶狀空間”的研究。此后便鮮有關(guān)于機動車道路的文化景觀研究[1-2]。這可能是部分由于我們不再樂觀地看待公路和它所代表的機動車文化，而把它們看作造成全球氣候變化的元兇。道路是“雜亂”的文化景觀，它并非基于傳統(tǒng)的、歷史悠久的人地關(guān)系，而是一種通用的全球文化的代表，并常作為其他文化景觀的負面因素而存在——它充當(dāng)了技術(shù)的傳輸帶，也充當(dāng)了棲息地的分隔板。

道路的“雜亂”也體現(xiàn)在他們難以恰當(dāng)?shù)厝谌攵x明確的文化景觀體系中。聯(lián)合國教科文組織為文化景觀定義了3個類別，如表1[3]。道路似乎屬于刻意創(chuàng)造的、“有明確定義的景觀”的范疇。然而，它也有 “有機演變的景觀”的特征，并且可以被視為“連續(xù)的景觀”，這一定義根據(jù)社會和經(jīng)濟對于科學(xué)技術(shù)的要求而提出，以應(yīng)對自然環(huán)境的相關(guān)問題。這些要求包括宏觀的融資和建設(shè)，使道路成為永久景觀的同時允許其發(fā)生動態(tài)變化。大量經(jīng)濟投資和大型的建設(shè)場地往往意味著道路更容易被適應(yīng)，而不是被取代或被遺棄。快速變化的機動車科技、迅速增長的人口及其流動性，導(dǎo)致道路使用率的增加、司機群體的增加與變化。因此，道路可以被描述為“快速變化”的景觀[4-5]。

Translator:

HE Ming-yi， who was born in 1991, is a Master student in School of Landscape Architecture, Beijing Forestry University.

WANG Liang, who was born in 1993, is a Master student

in School of Landscape Architecture, Beijing Forestry University

校對：

王晞月/1992年生/女/碩士/北京林業(yè)大學(xué)園林學(xué)院（100083北京）

Proofreading:

WANG Xi-yue, who was born in 1992, is a Master student in School of Landscape Architecture, Beijing Forestry University

另一個使道路變成“混亂”景觀的原因是，它很難被定義：到底什么是它的資源？是道路、道路使用權(quán)、道路上的視野，還是道路所穿越的景觀？在最近一次關(guān)于道路的文獻調(diào)查中，Grazuleviciute-Vileniske和Matijosaitiene試圖使用復(fù)合模型解決這個問題，可簡化如下：

A：作為文化遺產(chǎn)的道路（“歷史之路”）；B：作為文化遺產(chǎn)的道路景觀（“具有特殊意義的語境”）；C：道路景觀中的文化遺產(chǎn)（“緊鄰道路的歷史文物”）[6]。

Grazuleviciute-Vileniske和Matijosaitiene所提出的分類系統(tǒng)的意義在于它有助于確定什么樣的道路特征和元素是有價值的，并因此值得保護。如果道路被視為文化遺產(chǎn)，那么道路上的工程結(jié)構(gòu)（橋梁、涵洞、路緣石）是有價值的；如果道路周邊的景觀是文化遺產(chǎn)，那么從道路中望去的景觀元素（灌木籬墻，田地，農(nóng)用構(gòu)筑物或其他從道路中望去所見的構(gòu)筑物）是值得被保留的、有重要意義的元素；如果道路經(jīng)過文化遺產(chǎn)元素，那么道路旁邊的文化標(biāo)志物（歷史建筑、遺址、遺跡）就是值得被保護的目標(biāo)。然而，這種模式有一定的局限性，實際上許多道路都同時表現(xiàn)出了3個類別的特點。Grazuleviciute-Vileniske和Matijosaitiene也承認了這一事實，將“混合道路”作為分類框架里的一小部分。

這些大多涉及道路及其周圍環(huán)境之間的關(guān)系，它們使保護歷史悠久的道路景觀變得具有挑戰(zhàn)性。在道路上的變化可能會影響環(huán)境，而環(huán)境的變化也可能會影響到道路。當(dāng)從理論跨越到實踐時，往往只有極少的情況下，一條道路能夠恢復(fù)到它的歷史狀態(tài)，更多的往往是需要根據(jù)道路被修建、使用、或感知的方式進行保護和改造。在這篇文章中，列舉了美國地方、區(qū)域以及國家尺度上的4個案例，以闡述變化與環(huán)境如何與道路景觀的保護相關(guān)聯(lián)。下面的案例研究首先將道路分為4類，然后描述了道路的保護工作是如何作用于道路及其保護實踐方法的調(diào)整和轉(zhuǎn)換的。

2　案例研究1.邊緣巖石大道

1 環(huán)科羅拉多的巖石邊緣大道 （海蒂霍曼提供）Rim Rock Drive in Colorado（ Credit: Heidi Hohmann）

表1　世界遺產(chǎn)名錄之文化景觀，定義于《世界遺產(chǎn)文化景觀：保護和管理手冊》Tab. 1 World Heritage Categories of Cultural Landscapes, as defined in the World Heritage Cultural Landscapes: A Handbook for Conservation and Management

巖石邊緣大道（Rim Rock Drive），位于科羅拉州的弗魯塔，22.42英里（36.08km）長，可被定義為歷史性道路或是文化遺產(chǎn)道路。這是體驗科羅拉多國家紀(jì)念區(qū)（圖1）的主要路徑?？屏_拉多國家紀(jì)念區(qū)建立于1911年，是一個相對較小的（20 500畝/ 8 300hm2）的公園，用以保護前寒武紀(jì)、三疊紀(jì)、侏羅紀(jì)和白堊紀(jì)的重要地質(zhì)特征。巖石邊緣大道曾是一條原始的鄉(xiāng)間小道，由公園支持者約翰·奧托建造，但在大蕭條時期，國家公園管理局（NPS）利用民間護林保土隊（CCC）的勞動人員，擴展并修建了道路，將其用作汽車公路。這條道路的修建展示“史詩”般的工程圖景和及其陡峭的坡度；在其修建期間，大面積的巖石被炸開用以鋪設(shè)路基、在懸崖峭壁上打通隧道；建造大型擋土墻，將道路架設(shè)在狹窄的平緩區(qū)域。這里雖然氣候相對干燥，但經(jīng)常會有短暫而激烈的降雨，所以修建了大大小小共200個涵洞，大約每英里（1.61km）10個，用以及時排走降水。1931-1950年間，這條道路被記錄在美國歷史名勝名錄上，其重大的歷史意義在于它獨特的結(jié)構(gòu)和工程，并能夠?qū)⒔煌ê蛫蕵氛显谝黄稹?/p>

這條道路具有高度的完整性，并經(jīng)歷了相對較小的變化，大部分區(qū)域都處于正常狀態(tài)，鮮有因時間原因?qū)е碌墓こ虗夯陀捎谠冀Y(jié)構(gòu)缺陷造成的問題。但問題出現(xiàn)在比正常尺寸小的涵洞和洼地上，它們無法充分處理暴雨帶來的積水（這一問題自1939年就被發(fā)現(xiàn)）。傳統(tǒng)的基于識別和評估道路特征的保護方式已在道路保護方面表現(xiàn)得相當(dāng)出色。其中包括擋墻修復(fù)，道路重鋪，涵洞維修和更換。經(jīng)協(xié)商，美國聯(lián)邦公路管理局在1990年出版的《公路設(shè)計的靈活性》一書中限制了護欄只有最陡的路段才能使用。因此，沿著這條路上許多被認為是不太安全的歷史區(qū)域被保護了起來，目的是為了維護這條道路原始的駕駛體驗。

這條道路上導(dǎo)致變化發(fā)生的主要壓力來自于周邊地區(qū)人口的增加。2014年，科羅拉多州在美國的人口增長率中排名第四，主要因素是人口遷入；自2000年以來，大章克申附近的人口增加了43%[7]。這導(dǎo)致了長途旅游業(yè)和當(dāng)?shù)貖蕵窐I(yè)的增長：公園的到訪量在過去的兩年已達創(chuàng)紀(jì)錄水平，這意味著大量的的游客游覽過邊緣巖石大道。

作為人口增加的結(jié)果，這條道路主要發(fā)生了兩個變化，但這兩個變化都不會影響歷史悠久的道路本身的結(jié)構(gòu)。首先，是整體環(huán)境的變化，視角和視域都已經(jīng)發(fā)生了很大的變化，包括場地地理環(huán)境的背景中人類聚落和環(huán)境污染的出現(xiàn)等。這樣的變化或許在晚上表現(xiàn)更為明顯，當(dāng)光污染從停車場、購物中心引人注目的高壓鈉燈中射向道路的整體環(huán)境，這場景更像人類紀(jì)元而非前寒武紀(jì)。其次，是潛在社會功能的增加?？屏_拉多，特別是大章克申都因其擁有積極活躍的公民而聞名，現(xiàn)在這里還舉行重要的個人或團體的騎行、長跑等活動，包括重要的年度馬拉松。這條道路對于這些活動來說幾乎是完美的長度，同時擁有有趣的（和具有挑戰(zhàn)性的，2 000英尺（609.6m）高差）的路線。這樣的用途似乎對道路的結(jié)構(gòu)和保護有較少的影響，而對公園職工和維護方面的影響較大。作為一個公共景觀，公園對于這些活動應(yīng)該盡量縮減收費或者直接免費。

3　案例研究2.殖民地公路

殖民地公路長23英里（37.01km），可以被定義為歷史道路和擁有文化遺產(chǎn)景觀的公路。它位于弗吉尼亞州，于1933年由國家公園管理局設(shè)計建造，并作為殖民國家歷史公園的一部分。以布朗克斯河大道和弗農(nóng)山紀(jì)念公園作為范本，道路構(gòu)建出了“現(xiàn)代”的、富有藝術(shù)性的特征。這條路并沒有連接公園，而是連接了3個古跡景觀：詹姆斯敦（1607年英國人在美國的第一個聚居地），威廉斯堡（弗吉尼亞殖民地國會大廈）和約克城（康華里投降地，標(biāo)志著美國獨立戰(zhàn)爭的結(jié)束）。在施工建設(shè)的時候，殖民地公路采用了創(chuàng)新的技術(shù)，即暴露的骨料表面和3車道的設(shè)計。3車道設(shè)計并沒有道路標(biāo)線，可以被認為是種“退化”的設(shè)計模式，因為技術(shù)的改進以及中央分隔帶成為標(biāo)準(zhǔn)這樣的設(shè)計即被放棄。同時期的其他先進或創(chuàng)新的功能也被采用，包括流線型道路的設(shè)計，以及能將道路建在潮汐河口之上的現(xiàn)代混凝土橋梁。這些現(xiàn)代的橋梁與獨特的殖民地風(fēng)格手工磚建造的橋梁形成鮮明的對比，沿著道路看過去這樣的橋極具透視的美感。殖民地公路分前后兩個階段完成，從1933年到1941年和從1946年到1958年，中間被二戰(zhàn)打斷。值得注意的是，斯坦利·阿伯特曾在職業(yè)生涯初期為吉爾摩·克拉克設(shè)計過威徹斯特郡園道，并在上世紀(jì)30年代為國家公園管理局設(shè)計了藍嶺公園，在戰(zhàn)后主持設(shè)計了殖民地公路的第二階段。這條道路在歷史上具有重要意義，不僅因為其獨特的工程和景觀，更因為它與交通和歷史保護運動的之間的關(guān)聯(lián)[8]。

現(xiàn)在，道路保護的主要問題之一是周邊地區(qū)的人口增長。這條路曾經(jīng)穿過林地，現(xiàn)在它穿過的是住宅開發(fā)項目（圖2）。這種增長對道路景觀有兩個影響：首先是道路開始用作上下班的通勤，特別是在不斷發(fā)展的城市威廉斯堡的周邊區(qū)域。第二是由于發(fā)展的需要增加了防滲鋪設(shè)，結(jié)果增加了雨水徑流。道路的排水系統(tǒng)主要由直徑18-24英寸（45-60cm）的磚材涵洞組成，這個系統(tǒng)最初設(shè)計時用來處理鄉(xiāng)村徑流。如今，它難以處理日益增加的水量，造成道路積水，河岸的侵蝕以及林地退化等問題。國家公園管理局運用了傳統(tǒng)“翻修”的保護方法，對作為基礎(chǔ)設(shè)施的涵洞進行更新改造來解決這個問題。其中包括替換年久的涵洞管道，升級新的排水結(jié)構(gòu)，在一些區(qū)域使用比原始大小大兩倍的涵洞管道，特別是在某些關(guān)鍵洪水易發(fā)位置[9]。這些涵洞管道雖然更大了，但混凝土管道仍被磚所覆蓋包裹。他們的設(shè)計遵循美國保護指導(dǎo)準(zhǔn)則，這一準(zhǔn)則包含在在內(nèi)政部長的歷史地產(chǎn)處理標(biāo)準(zhǔn)中。這一標(biāo)準(zhǔn)中，歷史地產(chǎn)應(yīng)屬于現(xiàn)存的資源，與新的構(gòu)筑物區(qū)分開來（內(nèi)政部長）[10]。值得注意的是，這種恢復(fù)道路排水設(shè)施的措施是一種溫和的處理方式，因涵洞管道的變化方向平行于道路，并不在駕駛者的視域范圍之內(nèi)。

這個研究表明，隨著時間的推移人們對道路的感知是如何被變化的，以及它的使用方式可以通過怎樣的保護處理進行轉(zhuǎn)變。在其建造的時候被視作科技進步的代表，雖然有一部分道路是在第二次世界大戰(zhàn)后完成，只有不到50年的歷史，殖民地公路依然能夠被看作是一個歷史性的道路。同樣，一旦為游客和娛樂規(guī)定了特定的路線，道路的另一部分就會被看作是通勤的路線——這和巖石邊緣大道新增的休閑娛樂功能不同。令人高興的是，傳統(tǒng)的保護技術(shù)促進了功能的轉(zhuǎn)換，同時也減慢了特征的改變。

4　案例研究3.愛荷華林肯公路

2 穿越威廉斯堡的殖民地公路路線，展示了最近的房地產(chǎn)發(fā)展和集水區(qū)的水流方向.（谷歌地球（陸地衛(wèi)星）的地圖數(shù)據(jù)）Route of Colonial Parkway through Williamsburg, showing recent housing development and direction of water flow in watershed. （Map data from Google Earth (Landsat)）

3 用于分析歷史完整性道路基本元素，以惠特蘭西部的典型路段為例，1926年（提姆·凱勒和彼得·巴特勒提供）；下面的歷史圖片由密歇根大學(xué)專門收藏.Primary elements of the road used for analysis of historic integrity, based on typical section west of Wheatland, ca. 1926（Credits: Tim Keller and Peter Butler）; underlying historic image courtesy of University of Michigan Special Collections.

作為美國第一個橫貫大陸的高速公路之一，林肯高速公路橫跨美國3 400英里（5 470km），被認為是一條歷史性的道路或者說是一條象征著美國文化遺產(chǎn)的道路?！傲挚细咚俟贰边@個概念是由一群以Carl G. Fisher為首的汽車實業(yè)家在1913年提出的。這些實業(yè)家們同時也創(chuàng)立了林肯公路協(xié)會（LHA）。公路不是由聯(lián)邦政府資助的，而是由林肯公路協(xié)會（LHA）的地方分會和地方（州、縣）政府資助。他們時常會利用現(xiàn)有的道路和其他人建立的新路線去建設(shè)高速公路。這個建造過程通常包括“英里試建”策略，道路的建設(shè)者們運用最新的道路建設(shè)方法建立近1英里的段落，然后，地方政府可以從中選擇施工道路的標(biāo)準(zhǔn)，這些標(biāo)準(zhǔn)包括混凝土鋪裝、護欄和種植。其中最著名的案例位于伊利諾斯，是由著名建筑師Jens Jensen設(shè)計的。林肯公路是具有重大意義的，因為它培育了汽車文化，促進了道路建設(shè)的制度化和規(guī)范化，并最終促進了1956年聯(lián)邦公路法案和美國州際公路系統(tǒng)的形成。

在愛荷華州，建造了約長達300英里（480km）的林肯高速公路，其中一些路段沿著現(xiàn)有的礫石路線，一些沿著新路線。林肯公路協(xié)會愛荷華分部試圖確定一個“最佳路線”，所以路線前后被更改了許多次。最終，道路被重編為美國第30號高速公路。盡管愛荷華林肯高速公路成為了一個著名的國家線路，卻在1960年后被州際80號公路奪取了光彩，因為洲際80號公路復(fù)制了林肯公路南部40英里（64.37km）的線路。林肯公路隨后成為一個區(qū)域路線，主要是為本地人服務(wù)。今天，它仍具有重大歷史意義，因為它對于1913年至1956年美國交通運輸和汽車文化的發(fā)展有著顯著作用。

今天，各個州對于林肯高速公路的保護都各有策略。在愛荷華州，州和縣級政府對于道路的保護非常積極，因為愛荷華州有林肯公路協(xié)會的分部，這個分部在1992年重新建立，以“保存和恢復(fù)有關(guān)高速公路的記憶來歌頌它的意義和對國家的重要性”。在2004年，愛荷華交通部（IDOT）聘請愛荷華州立大學(xué)測繪、分析并策劃了一個歷史道路廊道的管理計劃，旨在解決3個主要問題：道路的歷史設(shè)計及特點，路旁建筑，可以追溯到1913-28年的周邊區(qū)域的發(fā)展。通過比較現(xiàn)有的條件和歷史照片，他們將交通部負責(zé)的工程層面和內(nèi)政部相關(guān)的歷史層面進行關(guān)聯(lián)整合[11]。這使得主要元素更具有識別性，這是保持道路景觀完整性與特征的關(guān)鍵，而次要元素的丟失可能對其完整性的保持并無影響。主要元素包括：線性關(guān)系，與鐵路的聯(lián)系，路旁種植，路面材料，道路通行權(quán)的范圍，路溝和路肩的材料，相關(guān)的設(shè)施，以及具有高度完整性和悠久歷史的土地使用狀況（例如，農(nóng)業(yè)使用）（圖3）。次級元素包括路面寬度、結(jié)構(gòu)、附屬零件、邊坡與邊溝，和周邊歷史上土地利用完整性較低的風(fēng)景。測繪和規(guī)劃需要大量利益相關(guān)者的投入，包括與縣級工程師、愛荷華林肯公路協(xié)會、30號公路聯(lián)盟（一個推動4車道的高速公路發(fā)展的地方經(jīng)濟發(fā)展集團）及愛荷華市民中焦點群體（包括農(nóng)民，上班族，進行休閑娛樂活動的使用者）進行協(xié)商。

凱勒和巴特勒的走廊管理計劃使得林肯公路成為了一個遺產(chǎn)景觀道。在美國，景觀道是聯(lián)邦公路協(xié)會（FHWA）國家項目的一部分，該協(xié)會在上世紀(jì)90年代為公路的防護提供資金。在2012后，這個項目被轉(zhuǎn)移至各州，并且自從2006年以后，林肯公路的愛荷華州段就已經(jīng)被愛荷華交通運輸部、當(dāng)?shù)乜h工程師和一個非盈利組織共同管理。

在景觀道的模式下，林肯公路的保護已很大程度上聚焦于因文化遺產(chǎn)旅游而得到發(fā)展的社區(qū)和經(jīng)濟。雖然關(guān)鍵的工程特征（如橋梁和礫石路段）被保留了下來，但是道路已被改造成了一個營銷工具，用以支持當(dāng)?shù)氐钠髽I(yè)和吸引旅游業(yè)繞過南部的州際公路。其他國家的研究顯示，道路名稱的選定能夠增加旅游量和旅游收入，雖然確切的經(jīng)濟效益很難量化[12]。在許多方面，今天的林肯高速公路不僅是一個地方，也是一個概念和品牌。盡管歷史性的元素正在丟失，道路的意向卻以林肯高速公路為載體而保持活力。在其他地方，一些社會事件使得林肯公路的記憶變得鮮活，例如長達300英里（482.80km）的義賣和一年一度的老爺車巡展。這種概念又經(jīng)眾多被批準(zhǔn)的獨立網(wǎng)站的宣傳而進一步被強化。這些網(wǎng)站通過使用智能手機即可觀看，免去了實際解說的需要并吸引了新的觀眾。盡管將林肯道路重塑為“景觀道”并沒有帶來道路本身保存價值的提升，但是它已經(jīng)顯著改變了道路的價值和體現(xiàn)方式，并通過道路穿行的社區(qū)表現(xiàn)出來。

5　案例研究4.愛荷華州州際80號公路

4 20世紀(jì)50年代完成后的80號州際公路，公路地圖（左）和近期實景（右）.（海蒂·霍曼提供）Interstate 80 in 1950s, after completion, from highway map　(left) and today (right). Credit: Heidi Hohmann

州際80號公路（I-80）取代林肯公路作為愛荷華州最重要的東西跨大陸運輸?shù)缆?。這條道路綿延306英里（492km），是1956年聯(lián)邦援助公路行動（也被稱為國家州際公路和國防公路行動）的一部分，這個項目提供250億美元用于建設(shè)美國41 000英里（65 983.10km）的公路。州際80號公路的設(shè)計參照19世紀(jì)50年代的FHWA標(biāo)準(zhǔn)，是一個菱形和四葉式固定的4車道立體交叉道，其路線高效，具有長螺旋的曲線形態(tài)和路旁的服務(wù)設(shè)施。這條道路用時14年建造完成，它的第一段是在1985年建造完畢，最后一段在1966年竣工。在20世紀(jì)80年代早期，交通量就已經(jīng)達到了設(shè)計的預(yù)期，所以在1985年到1988年間，對道路全長進行了重新建設(shè)（圖4）。

洲際80號公路是一條重要的越野路線，承載著大量的卡車和汽車的通行。在愛荷華州，它穿過了美國的一個主要農(nóng)業(yè)區(qū)——“美國玉蜀黍種植地帶”，這是一個由玉米和大豆組成的廣闊的景觀，其上點綴著歷史上和現(xiàn)代農(nóng)業(yè)使用的農(nóng)用構(gòu)筑物。這種景觀雖然在其農(nóng)業(yè)利用的演變過程中具有重要意義，可以被認為是美國的農(nóng)業(yè)遺產(chǎn)的一部分，但道路本身更多的被認為是文化遺產(chǎn)，傳遞著該國對汽車文化的熱愛。

此外，美國保護指南顯示，洲際80號公路如同其余大多數(shù)州際公路系統(tǒng)一樣有資格錄入美國歷史名勝登記冊，因其技術(shù)上的歷史意義以及它與交通發(fā)展歷史的聯(lián)系。在2005年3月10日，歷史保護咨詢委員會確認了州際公路系統(tǒng)的資格，并確認更新的道路，以滿足未來的交通需求。并且，委員會通過了“第106條關(guān)于對州際公路系統(tǒng)豁免的實施”。這條協(xié)議將洲際80號公路和部分其他州際公路系統(tǒng)從第106條國家歷史保護行動（NHPA）中脫離，除了沿路線的一些關(guān)鍵功能（主要是橋梁、工藝品和具有特別意義的工程）。[13]

洲際80號公路向我們清晰地展示了道路作為文化景觀的“混亂”。盡管它同時作為一種歷史景觀和一種日常/普通文化景觀存在，第106條法案的豁免從本質(zhì)上確保了州際80號公路和美國其他的州際公路一樣，能夠不斷地改變以適應(yīng)更多的運輸貨物量和經(jīng)濟需求。事實上，當(dāng)前（2016）對州際80號公路的規(guī)劃研究以及未來的規(guī)劃方案提出了繼續(xù)擴大路基的設(shè)想，即擴展至6車道以為未來發(fā)展提供充足的空間。

然而，為了努力去尋求保護這條道路的辦法，2004年愛荷華州立大學(xué)的研究人員說服了愛荷華交通部不僅要考慮規(guī)劃和保護這條路，而且還要考慮更宏觀的愛荷華景觀，于是于2006年開始了一項“維護愛荷華的形象”的走廊管理計劃。它運用景觀視覺質(zhì)量的研究方法，試圖確定重要的自然和文化資源。這些資源有助于直觀的駕駛體驗，反映出國家的文化和歷史，代表著自然景觀和典型的愛荷華式開發(fā)的景觀。[14]研究調(diào)查了3英里（4.83km）寬道路走廊的兩側(cè)：首先記錄一些要素，如形式、線性、顏色和具有視覺體驗的紋理特征，然后確定經(jīng)濟、土地、文化、生態(tài)和具有過去歷史及未來發(fā)展特征的道路交通資源。該計劃還確定了經(jīng)濟增長的區(qū)域和指導(dǎo)方針，以及沿著走廊的城市發(fā)展，試圖保持風(fēng)景歷史資源和經(jīng)濟增長之間的平衡，兼顧愛荷華州的新舊景觀，并且允許愛荷華州“未來景觀”的發(fā)展。也就是說，該項目不僅試圖尋求歷史文化的價值，還在尋找道路在先今時代的意義。這個項目對于道路保護來說是十分重要的，因為它與傳統(tǒng)的保護方法相反。不是把歷史看作一組靜態(tài)的文物或視域，“愛荷華形象”計劃將歷史納入一個更廣泛的文化定義，旨在保護一個不斷發(fā)展的文化和變化的景觀，而不是一組靜態(tài)的文物。

6　總結(jié)

總之，這些研究案例都表現(xiàn)是近100年或不到100年內(nèi)的景觀需要思考的事情，這個年限涵蓋了（長壽的）人類的壽命。這些道路確實是一種快速變化的景觀，所以那些“保護”它們的想法可能有點言不由衷。正如洲際80號道路所顯示的那樣，道路的保護與下一個創(chuàng)新的設(shè)計之間相差并不遠。這些文化景觀使得保護主義者們面臨著對于重新設(shè)計與保存的反對意見，因為一方面，技術(shù)促進了改革，而另一方面，保護主義者們卻想凍結(jié)景觀中的時間。機動車道路使得保護主義者們很難去將歷史浪漫化；相反，他們要求設(shè)計師、規(guī)劃師和道路使用者把過去和未來放在同等位置，因為道路在他們的使用過程中可能是普通的景觀，然而在設(shè)計中卻可以是十分精彩的。無論從客觀還是隱喻的角度看，道路都穿行在景觀中，這使得道路作為文化景觀的界定和劃分變得更困難。在景觀保護當(dāng)中，最大的兩個挑戰(zhàn)可能就是背景環(huán)境和變革間的沖突，而道路景觀需要我們同時關(guān)注這兩點。

1　Introduction

Following a spate of optimistic, "everyday" cultural landscape studies at the end of the twentieth century, such as J.B. Jackson's "ideological" studies and Grady Clay’s study of roadside "strips," automobile roads have largely disappeared from recent cultural landscape research[1-2]. This may in part be due to the fact that we no longer think about roads-and the cars they support-optimistically, but rather as contributors to global climate change. Roads are "messy" cultural landscapes.They are not based on traditional, time-honored humanland relationships. Instead, they represent a generic, global culture, and in fact often act as disruptors of other cultural landscapes-as conveyors of technology and dividers of habitat.

Roads are also “messy” in that they don’t neatly fit into defined cultural landscape hierarchies. UNESCO defines cultural landscapes in three categories, as seen in Table 1[3]. Roads would appear to belong in the category of intentional, "clearly-defined landscapes." However, they also share characteristics with "organically evolved landscapes," and might be considered "continuing landscapes," defined by social and economic imperatives of technology in response to the natural environment.These imperatives, which include heroic scales of financing and construction, make roads both highly permanent landscapes yet also liable to change. High economic investment and large construction sites mean roads are oftenbut not always-more liable to be adapted than replaced or abandoned. The rapid pace of change in automobile technology and population growth and mobility) leading to increased roadway use are additional drivers of change and evolution. Stated another way, roads might be described as "fast change" landscapes.[4-5]

The other issue that makes roads "messy" landscapes is that they are difficult to define: what is the resource? Is it the road, the right of way, the view from the road, or the landscape the road moves through? In a recent survey of roadway literature, Grazuleviciute-Vileniske and Matijosaitiene address these questions in a complex model, which may be simplified as follows:

A. Road as cultural heritage("historic road")

B. Road landscape as cultural heritage ("significant context")

C. Cultural heritage in road landscape ("historic objects next to road")[6]

The classification system Grazuleviciute-Vileniske and Matijosaitiene propose is perhaps most useful in that it helps determine what road features and elements are highly valued, and hence worthy of protection.If the road is considered as cultural heritage, then engineering structures(bridges, culverts, curbs) are worthy; If the road’s surrounding landscape is considered as cultural heritage, then the landscape element in view from the road (hedgerows, fields, agricultural or other structures in view from the road) are the significant elements to be preserved; and if the road goes past cultural heritage elements, then cultural features next to the road (historic buildings, sites, monuments) are those elements targeted elements for preservation. However, this model has limitations, a key one being the fact that many roads exhibit characteristics of all three of these categories. Although Grazuleviciute-Vileniske and Matijosaitiene concede this, the “mixed road”classification is a small part of their classification framework.

These issues-which are largely concerns about the relationship between a road and its surrounding context-make preserving historic road landscapes challenging. Change in the road may affect context and change in context may affect the road. When moving beyond documentation to active work, it is often only in rare cases where a road may be restored back to its historic conditions; more often preservation requires a transformation or adaptation in the way the road is constructed, used, or perceived. In this article, four case studies at local, regional, and national scales from the United States are used to discuss the ways change and context interrelate in the preservation treatment of road landscapes. The following case studies first classify the four roads and then describe how preservation efforts have resulted in adaptations or transformations of both the roads and of approaches to preservation practice.

2　Case Study 1. Rim Rock Drive

Rim Rock Drive, located in Fruita, Colorado is 22.42 miles long and can be classified as a historic road or a road that is cultural heritage. It is the primary means of experiencing Colorado National Monument [Figure 1].Colorado National Monument is a relatively small (20,500 acres/8,300 ha) park established in 1911 to protect significant geological features of the Pre-Cambrian, Triassic, Jurassic, and Cretaceous periods.Rim Rock Drive began as crude trail built by a park booster John Otto, but during the Depression the National Park Service (NPS), using labor from the Civilian Conservation Corps (CCC), extended and constructed Rim Rock Drive as a motor road. The road exhibits "heroic" engineering, scaling steep slopes; in its construction, large areas of rock were dynamited to create the roadbed and tunnel through cliffs; and large retaining walls were built to pin the road to narrow ledges. Though relatively dry, the climate is characterized by brief but intense rainfalls, so over 200 culverts, approximately 10 per mile, both large and small, were constructed to move water across the roadway. The road is listed on the U.S. National Register of Historic Places and is historically significant for its distinctive construction and engineering and for its association with transportation and recreation during the years 1931-1950.

The road has high integrity to the historic period and has experienced relatively little change, mostly "normal," age-related deterioration and problems due to original construction flaws. These include undersized culverts and swales unable to adequately handle storm water (a problem recognized since 1939).Traditional preservation treatment-based on identification and assessment of the road’s character-defining features-has been quite successful at maintaining the road. This work has included retaining wall repair, roadway resurfacing, and culvert repair and replacement. A major treatment success has been limiting guardrails to only the steepest sections of the road through negotiations made possible following the publication of Flexibility in Highway Design by the U.S. Department of Transportation Federal Highway Administration in the late 1990s. Consequently, there are a number of locations along this road where historic conditions that might be considered less safe have been preserved in order to maintain the road’s original driving experience.

The major pressure on this road that has led to change has been population increase in surrounding areas. In 2014, Colorado was 4th in rate of population growth in the U.S., primarily due to in-migration; the population of nearby Grand Junction has increased 43% since 2000[7]. This has led to increased longer distance tourism and increased local recreation: visitation in the park has been at record levels the past two years, meaning record numbers of visitors have traveled Rim Rock Drive.

Two major transformations have occurred as a result of increased population, neither of which impact the fabric of the historic road per se.First is a contextual transformation, as views and view sheds have significantly changed, to include human settlement and pollution in the background of the geologic futures.Such changes are perhaps more visible at night, when light pollution from high-pressure sodium lighting of parking lots andshopping centers—however beautiful or striking—changes the overall setting of the road, making it more Anthropocene than Pre-Cambrian. Second, are unenvisioned new social uses. Colorado generally, and Grand Junction specifically, is known for its active citizenry and the road now hosts significant new uses of biking and running, both individual and group events, including a major annual marathon. The road is an almost perfect length for this event and boasts an interesting (and challenging, given the road's 2,000 foot elevation change) route for runners. Such uses seem to have less of an impact on the road’s fabric and preservation and more of an issue in terms of park staffing and support. As a public landscape, the park charges minimal or no fees for these uses.

3　Case Study 2. Colonial Parkway

Colonial Parkway is 23 miles long and can be classified as both a historic road and as a road that has cultural heritage in its landscape. It is located in Virginia, and was designed and constructed beginning in 1933 by the National Park Service as part of Colonial National Historical Park. Using the Bronx River Parkway and the Mount Vernon Memorial Parkways as precedents the road was constructed as a state of the art "modern" parkway. However, it did not link parks, but rather three historic sites/landscapes: Jamestown (site of first English settlement in the United States in 1607); Williamsburg (Virginia’s colonial capitol) and Yorktown (site of Cornwallis’s surrender marking the end of the American Revolutionary War). At the time of its construction, Colonial Parkway was technologically innovative with an exposed aggregate surface and a three-lane design. The three-lane design, without road striping, can be considered a "vestigial" design model, since it was later abandoned as road technology improved and a central median became standard. Other advanced or innovative features for the time included the road's stream-lined, modern concrete bridges that carried the road over tidal estuaries. These modern bridges contrasted with the more picturesque, overpass bridges which were constructed of handmade Colonial-style brick, and were seen in the perspectival view down the road. Colonial Parkway was completed in two phases, from 1933 to 1941 and from 1946 to 1958, before and after World War II.Notably, Stanley Abbott-who had "cut his teeth" working on the Westchester County Parkways for Gilmore Clarke prior to designing the Blue Ridge Parkway for the National Park Service in the 1930s-managed the second, postwar phase of the parkway’s construction. The road is historically significant for its distinctive construction and landscape architecture as well as for its associations with transportation and the historic preservation movement[8].

Today, one of the major preservation issues for this primarily local road is population growth in the surrounding region. The road once passed through woodlands; now it passes through housing developments [Figure 2]. Such growth in the road’s landscape context has had two impacts: the first is use of portions of the road for commuting, particularly around the growing city of Williamsburg. The second is increased storm water run-off due to increased impervious paving as a result of development. The road's drainage system, mostly comprised of brick culverts sized 18 to 24 inches (45 to 60 cm) in diameter, was originally designed to handle rural stream flows. Today it cannot handle increased volumes, causing roadway flooding, significant stream bank erosion, and woodland degradation. The National Park Service has used a traditional preservation approach of "rehabilitation"-upgrading culverts as infrastructure-to address this problem. This has included replacing historic culverts and drainage structures with new, larger culverts-in some cases more than twice the original size, particularly in key in key flood locations[9].These culverts, though much larger and constructed of concrete are clad in brick. Their design has followed U.S. preservation guidelines as contained in the Secretary of Interior's Standards for the Treatment of Historic Properties, in that they are compatible with the existing resource yet are clearly distinguishable as new construction (Secretary of the Interior)[10].It is worth noting that this rehabilitation of the road’s drainage infrastructure is also mitigated by the fact that it is largely invisible, as culvert changes run parallel to the road and are out of the motorist's view shed.

This case study shows how perception of a road can be transformed over time and how its use can be transformed through preservation treatment. Seen as a technological advance at the time of its construction, today Colonial Parkway is viewed as a historic roadway, though parts of it, completed after World War II, are only barely 50 years old. Similarly, once a tourist and recreation route, portions of it are now seen as a commuting route. This is in contrast to Rim Rock Drive, where recreational uses have increased. Happily, traditional preservation techniques have facilitated changing uses while at the same time mitigatingcharacter change.

4　Case Study 3. Lincoln Highway in Iowa

As one of the first trans-continental highways in the United States, traversing 3,400 miles (5,470 km) across the United States, the Lincoln Highway can be considered to be a historic road or a road that is cultural heritage of the United States. It was conceptualized in 1913 by a group of automobile industrialists headed by Carl G. Fisher, who organized the Lincoln Highway Association (LHA). The road was not federally funded, but instead financed by local chapters of the LHA and local (state and county) governments, who in some cases utilized existing roads and in others built new alignments.The process often included the construction of "seedling miles" where road proponents built short, 1-mile segments using the most up-to-date road construction. Local governments could then implement or aspire to the preferred road standards, which included concrete paving, guardrails and plantings.Perhaps the most famous seedling mile was located in Illinois and was designed by noted landscape architect Jens Jensen. The Lincoln Highway is significant in that it fostered an automobile culture, systemized and standardized road construction, and eventually helped lead to the 1956 Federal Highway Act and the U.S. Interstate System.

In Iowa, approximately 300 miles (480 km) of Lincoln Highway was constructed, some along existing gravel routes and some along new alignments. The road was also rerouted numerous times as the Iowa Chapter of the LHA sought to determine the "best route" across the state. Eventually, the road was renumbered as U.S. Highway 30.Although it became a well-known national route, after 1960, the Lincoln Highway in Iowa was overshadowed by Interstate Highway 80, which duplicated the Lincoln Highway route 40 miles to the south. The Lincoln Highway subsequently became a regional route, primarily serving state audiences. Today it is historically significant for its association with transportation and the development of automobile culture in the United States for the years 1913 to 1956.

Today, individual states have varying approaches to the preservation of the Lincoln Highway. In Iowa, state and county governments are active in the road’s preservation as is the Iowa Chapter of Lincoln Highway Association, which was re-established in 1992 to "preserve and restore the memory of the highway to celebrate its meaning and national significance." In 2004, the Iowa Department of Transportation (IDOT) employed Iowa State University to map, analyze and create a corridor management plan for the historic roadway, addressing 3 main issues:the road’s historic design and features; its roadside architecture, and adjacent development dating to 1913-28. Comparing existing conditions and historic photos, they correlated IDOT engineering elements with the Secretary of Interior’s aspects of integrity[11]. This led to the identification of primary elements-key to maintaining integrity and character, and secondary elements, which could potentially be lost and still maintain integrity. Primary features included: alignment, association with the railroad, roadside vegetation, pavement material, width of the right-of-way, ditch and shoulder material, associated utilities, and adjacent landscapes with high integrity of historic land use (e.g., agricultural use) [Figure 3]. Secondary features included pavement width, structures, appurtenances, ditch slopes, and adjacent landscapes with low integrity of historic adjacent land use. Mapping and planning required extensive stakeholder input and included consultations with county engineers, the Iowa Lincoln Highway Association; the Highway 30 Coalition (a local economic development group promoting development of a 4-lane highway); and focus groups of Iowa citizens (including farmers, commuters, recreational users).

Keller and Butler's Corridor Management Plan led to the designation of the Lincoln Highway as a Heritage Scenic Byway. Scenic Byways in the U.S. were a part of a national program of the Federal Highway Association (FHWA), which provided funding for road protection in the 1990s.After 2012, the program was shifted to the states, and since 2006, the Lincoln Highway Byway in Iowa has been managed by a non-profit organization in conjunction with the Iowa Department of Transportation and local county engineers.

Under the scenic byway model, preservation of the Lincoln Highway has been strongly focused on community/economic development through cultural heritage tourism. Although key engineering features (such as bridges and gravel segments) are preserved, the road has been transformed into a marketing tool to support local businesses and draw tourism to places bypassed by the interstate highway that runs to the south.Studies in other states show byway designations increase tourism and tourism revenues, though exact economic benefits can be hard to quantify[12]. In many ways, the Lincoln Highway today is as much an imageor a brand as it is a place. Where historic elements are missing, the image of the roadway is kept alive via Lincoln Highway signage. In other places, social events, such as a 300-mile long rummage sale and an annual vintage car tour, keep the memory of Lincoln Highway alive. The image is further supported by numerous sanctioned and independent Lincoln Highway websites. Viewed on a smart phone, these sites obviate the need for physical interpretation and reach new audiences. Although the recasting of the Lincoln Highway as a "scenic byway" has not necessarily led to improved preservation of the physical road, it has significantly changed the way the road is valued and interpreted by the communities it passes through.

5　Case Study 4. Interstate 80 in Iowa

Interstate 80 (I-80) replaced the Lincoln Highway as Iowa's most important east-west/ trans-continental transportation road. The road, running 306 miles (492 km) through the state, was part of the Federal-Aid Highway Act of 1956 (also known as the National Interstate and Defense Highways Act), which provided $25 billion to build 41,000 miles of highway across the United States. Interstate-80 was designed to 1950s FHWA standards as a four-lane road with diamond and cloverleaf interchanges, efficient routing, long, spiral curves and services placed outside the right of way. The road was built over 14 years, with its first sections completed in 1958, and its last sections in 1966.By the early 1980s, traffic volumes had reached design capacity and the road was reconstructed along its full length from 1985-1988 [Figure 4].

I-80 is a significant cross-country route and carries large volumes of trucks and automobiles. In Iowa, it passes through one of the United States’ key farming regions, the "corn belt," a vast landscape of corn and soybean fields, dotted with historic and contemporary agricultural structures. This landscape, though continuing in its evolution in terms of agricultural use, can be considered part of the United States’ agricultural heritage, as much as the road itself can be considered cultural heritage, expressing the country's love of the automobile.

In addition, at more than 50 years old, I-80, like the much of the rest of the Interstate System, is, according to U.S. preservation guidelines, technically "historic" and eligible for the U.S. National Register of Historic Places for its association with transportation history. Recognizing both the eligibility of the interstate system and acknowledging the desire to update the roads to meet future transportation demands, on March 10, 2005, the Advisory Council for Historic Preservation adopted the "Section 106 Exemption Regarding Effects to the Interstate Highway System." This agreement exempts I-80 and the rest of the Interstate System from Section 106 of the National Historic Preservation Act (NHPA), with the exception of key features along the route (mostly bridges, artwork, and significant engineering)[13].

I-80 shows clearly the "messiness" of roads as cultural landscapes. Although it simultaneously exists as both a "historic landscape" and an "everyday/ordinary cultural landscape," the "Section 106 Exemption" essentially ensures that I-80, like other interstates in the United States, will continue to change and transform to meet economic and functional imperatives of transporting more people and goods. Indeed, the current (2016) planning study and guidelines for the future of I-80 plan proposes to continue to expand the roadway, to include 6 lanes of traffic plus room for future expansion.

However, in an effort to look at the preservation of this roadway differently, in 2004researchers at Iowa State University convinced the Iowa Department of Transportation (IDOT) to consider planning and preserving not just the road, but also the larger Iowa landscape it moves through in a 2006 Corridor Management Plan entitled "Maintaining the Image of Iowa." Applying methods from landscape visual quality studies, this project sought to identify the significant natural and cultural resources that "contribute visually to the driving experience, reflect the culture and history of the state, and represent the natural and developed landscapes that typify Iowa."[14]It surveyed a 3-mile wide corridor on both sides of the road: first documenting the elements of form, line, color and texture features that characterized the visual experience and then identifying economic, agrarian, cultural, ecological and transportation resources that characterized the past history and future development of the road. The plan also identified areas and guidelines for economic growth and urban development along the corridor, seeking to balance preservation of scenic and historic resources with growth and development, embracing the "old landscape"of Iowa and the "new landscape" of Iowa, and accepting the development of a "future landscape" of Iowa. Stated another way, the project sought to identify the cultural significance not just ofthe past, but also of the present. This project is significant for roadway preservation because it sits in contrast to the idea of traditional preservation approaches. Instead of seeing history as contained in a set of static artifacts or view sheds, the "Image of Iowa" plan in corporate history into a broader definition of culture and seeks to preserve an evolving culture and a changing landscape rather than a set of static artifacts.

6　Conclusion

In conclusion, it is worth considering that these case studies address landscapes at or just under 100 years old, encompassing the life span of a (long-lived) human. These roads are indeed "fastchange" landscapes, and the idea of "preserving" them may actually be somewhat disingenuous. As I-80 in particular shows, the preservation of a road is actually never very far away from the next innovation in design. These cultural landscapes require preservationists to confront opposing ideals in design and preservation, as on the one side technology promotes change while on the other preservationists seek to freeze landscapes in time. Automobile roads make it difficult for preservationists to romanticize the past; instead, they require designers, planners, and road users to juxtapose the past and the future, because roads are both ordinary landscapes in their usage yet can be extraordinary in their design. And roads make it difficult to isolate and draw boundaries around cultural landscapes because they run through landscapes, both metaphorically and physically. Context and change are probably the two greatest challenges in landscape preservation, and road landscapes make us look at both.

（References）：

[1]Jackson, J.B. “Roads Belong in the Landscape”in A Sense of Place, A Sense of Time New Haven: Yale University Press. 1994.

[2]Clay, Grady. “Strips” in Close-Up: How to Read the American City. New York: Prager, 85-109.1973.

[3]Mitchell, N., M. Rossler, and P. M.Tricaud, (eds). World Heritage Cultural Landscapes: A Handbook for Conservation and Management. World Heritage Papers 26, Paris: UNESCO. 2009.

[4]Selman, Paul. Sustainable Landscape Planning: The Reconnection Agenda. New York: Routledge. 2012.

[5]Roe, Maggie. "Exploring Future Cultural Landscapes"in Maggie Roe and Ken Taylor (eds), New Cultural Landscapes. New York: Routledge, 241-269. 2014.

[6]Grazuleviciute-Vileniske, Indre and Irina Matijosaitiene. "Cultural Heritage

of Roads and Road Landscapes: Classification and Insights on Valuation." Landscape Research, 35:4, 391-413. 2010.

[7]Svaldi, Aldo. "Colorado Ranks Fourth Among States for Population Gains." Denver Post, 23 December 2014.http:// www.denverpost.com/2014/12/23/colorado-ranks-fourthamong-states-for-population-gains/

[8]Heritage Landscapes (Patricia O'Donnell, Principal). "Cultural Landscape Report for Colonial Parkway, Part 1: Site History and Existing Conditions." National Park Service. 1997.

[9]National Park Service, Colonial National Historical Park. "Environmental Assessment/Assessment of Effect: Redesign Parkway Drainage along Papermill Creek Watershed." 2006. https://parkplanning.nps.gov/document. cfm?parkID=218&projectID=13388&documentID=13911.

[10]Secretary of the Interior. Standards for the Treatment of Historic Properties. National Park Service. 1995. https:// www.nps.gov/tps/standards/four-treatments.htm

[11]Keller, T., P. Butler, and C. J. Seeger. "The Tale of Two Corridors: The Lincoln Highway and Interstate 80: Issues in managing Historic and Contemporary Routes." Presented at Preserving the Historic Road in America Conference. National Trust for Historic Preservation. Portland, Oregon. 2005.

[12]Petraglia, Lisa and Glen Weisbrod. "Review of Impact Studies Relative to Scenic Byway Designation." National Scenic Byways Resource Center. 2001.

[13]"Exemption Regarding Historic Preservation Review Process for Effects to the Interstate Highway System." Federal Register Vol 70: 46 (10 March 2005), 11928-31. http://www.achp.gov/docs/final_interstate_exemption_ notice.pdf

[14]Seeger, Christopher J. "Maintaining the Image of Iowa: Mapping the Natural, Cultural, Agrarian, and Scenic Features Adjacent to Iowa's Interstate 80." Presented at the Transportation Research Board Annual Meeting. 2004.

Considering Change and Context in the Preservation of Road Landscapes

The literature of cultural landscapes contains abundant road studies by Jackson, Clay, and others. However, the actual preservation of transportation corridors poses numerous challenges, most of which stem from their long and narrow character: although preservation of a road’s structures (roadbed, curbs and culverts) may be straightforward due to their relative simplicity and the road’s jurisdiction under a single agency, preservation of the corridor context is usually more difficult, due to its vast expanse, myriad stakeholders, and rapid change. Situated in larger social and environmental networks of communication and transportation and affected by rapid technology change, roads are “fast change” landscapes, their use, experience and character evolving over time. Given such changes how can preservation be accomplished—or justified—over the long distances of transportation corridors?Four case studies from the United States explicate preservation challenges at local, regional and national scales.Discussion of parkways, scenic byways, and highways describes preservation approaches that permit ongoing transformation and evolution of these resources.

Road; Landscape; Context; Parkway; Byway

TU986

A

1673-1530（2016）08-0058-11

10.14085/j.fjyl.2016.08.0058.11

2016-07-06

2016-08-03

海蒂·霍曼，美國風(fēng)景園林師協(xié)會會員，注冊風(fēng)景園林設(shè)計師，為美國愛荷華州立大學(xué)風(fēng)景園林副教授。

Author:

Heidi Hohmann, ASLA, RLA, is an Associate Professor of Landscape Architecture at Iowa State University, Ames, IA, USA.

何明一/1991年生/男/碩士/北京林業(yè)大學(xué)園林學(xué)院（100083北京）

王亮/1993年生/男/碩士/北京林業(yè)大學(xué)園林學(xué)院（100083北京）