Editing Road (section)

==Environmental performance==
{{Main|Environmental impacts of roads}}
[[File:Aab Pasadena Highway Los Angeles.jpg|thumb|Air pollution along Pasadena Highway in Los Angeles]]
Careful design and construction of a road can reduce any negative environmental impacts.
Water management systems can be used to reduce the effect of pollutants from roads.<ref>{{Cite book|url=https://books.google.com/books?id=cdc3AQAAMAAJ&q=Drainage+systems+can+be+used+to+reduce+the+effect+of+pollutants+from+roads&pg=PA293|title=Pittsburgh Light Rail Transit Reconstruction: Environmental Impact Statement|date=1979|publisher=The Administration|language=en}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=9o7rq6WnSXEC&q=Drainage+systems+can+be+used+to+reduce+the+effect+of+pollutants+from+roads&pg=PA312|title=The Ecology of Transportation: Managing Mobility for the Environment|last1=Davenport|first1=John|last2=Davenport|first2=Julia L.|year=2006|publisher=Springer Science & Business Media|isbn=978-1-4020-4504-2|language=en}}</ref> [[Rain]]water and [[snowmelt]] running off of roads tends to pick up gasoline, [[motor oil]], [[heavy metals]], [[waste|trash]] and other pollutants and result in [[water pollution]]. Road runoff is a major source of [[nickel]], copper, [[zinc]], [[cadmium]], lead and [[polycyclic aromatic hydrocarbon]]s (PAHs), which are created as [[combustion]] byproducts of gasoline and other [[fossil fuel]]s.<ref>{{cite book |title=Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers |publisher=CRC/Lewis Publishers |location=New York |year=2001 |isbn=978-0-87371-924-7 |chapter-url=http://unix.eng.ua.edu/~rpitt/Publications/BooksandReports/Stormwater%20Effects%20Handbook%20by%20%20Burton%20and%20Pitt%20book/MainEDFS_Book.html |first1=G. Allen Jr. |last1=Burton |first2=Robert |last2=Pitt |chapter=2 |access-date=2009-04-30 |archive-date=2009-05-19 |archive-url=https://web.archive.org/web/20090519035716/http://unix.eng.ua.edu/~rpitt/Publications/BooksandReports/Stormwater%20Effects%20Handbook%20by%20%20Burton%20and%20Pitt%20book/MainEDFS_Book.html |url-status=dead }}</ref>

[[De-icing]] chemicals and sand can run off into roadsides, contaminate [[groundwater]] and pollute [[surface water]]s;<ref>Charles Seawell and Newland Agbenowosi (1998). [http://www.cee.vt.edu/ewr/environmental/teach/gwprimer/roadsalt/roadsalt.html "Effects of Road Deicing Salts on Groundwater Systems."] {{webarchive |url=https://web.archive.org/web/20090521095505/http://www.cee.vt.edu/ewr/environmental/teach/gwprimer/roadsalt/roadsalt.html |date=2009-05-21 }} Virginia Polytechnic Institute, Department of Civil Engineering.</ref> and [[road salt]]s can be toxic to sensitive plants and animals.<ref>University of Minnesota (2009). [http://www1.umn.edu/news/news-releases/2009/UR_RELEASE_MIG_5295.html "U of M research finds most road salt is making it into the state's lakes and rivers."] 2009-02-10.</ref> Sand applied to icy roads can be ground up by traffic into fine particulates and contribute to air pollution.

Roads are a chief source of [[noise pollution]]. In the early 1970s, it was recognized that design of roads can be conducted to influence and minimize noise generation.<ref>{{cite journal |url=https://doi.org/10.1007%2FBF00159677 | doi=10.1007/BF00159677 | title=Analysis of highway noise | year=1973 | last1=Hogan | first1=C. Michael | journal=Water, Air, and Soil Pollution | volume=2 | issue=3 | pages=387–392 | bibcode=1973WASP....2..387H | s2cid=109914430 }}</ref> [[Noise barrier]]s can reduce noise pollution near built-up areas. Regulations can restrict the use of [[engine braking]].

[[Motor vehicle emissions]] contribute [[air pollutant|air pollution]]. Concentrations of air pollutants and adverse [[respiratory]] health effects are greater near the road than at some distance away from the road.<ref name="carbonblack">{{cite web |title= Traffic-related Air Pollution near Busy Roads |publisher= American Journal of Respiratory and Critical Care Medicine Vol 170. pp. 520–26 |year= 2004 |url= http://ajrccm.atsjournals.org/cgi/content/full/170/5/520 |access-date= 2007-10-11 |archive-date= 2009-04-02 |archive-url= https://web.archive.org/web/20090402133440/http://ajrccm.atsjournals.org/cgi/content/full/170/5/520 |url-status= dead }}</ref> [[Road dust]] kicked up by vehicles may trigger [[allergic]] reactions.<ref>[https://www.sciencedaily.com/releases/1999/11/991130062843.htm "Road Dust – Something To Sneeze About."] ''Science Daily,'' 1999-11-30.</ref> In addition, on-road transportation greenhouse gas emissions are the largest single cause of climate change, scientists say.<ref>{{cite journal|title=Attribution of climate forcing to economic sectors |doi=10.1073/pnas.0906548107 |pmid=20133724 |volume=107 |issue=8 |journal=Proceedings of the National Academy of Sciences |pages=3382–87|year=2010 |last1=Unger |first1=N. |last2=Bond |first2=T.C. |last3=Wang |first3=J.S. |last4=Koch |first4=D.M. |last5=Menon |first5=S. |last6=Shindell |first6=D.T. |last7=Bauer |first7=S. |pmc=2816198 |bibcode=2010PNAS..107.3382U |doi-access=free }}</ref>