Editing Left- and right-hand traffic (section)

====United States====
In the late 18th century, right-hand traffic started to be introduced in the United States based on [[teamster]]s' use of large freight wagons pulled by several pairs of horses and without a driver's seat; the (typically right-handed) [[postilion]] held his whip in his right hand and thus sat on the left rear horse, and therefore preferred other wagons passing on the left so that he would have a clear view of other vehicles.<ref>{{cite book|url=https://books.google.com/books?id=lyoDAAAAMBAJ&pg=PA37 |title=Why We Drive on the Right of the Road, ''Popular Science Monthly'', Vol.126, No.1, (January 1935), p.37 |access-date=25 April 2012|date=January 1935 }}</ref>{{Better source needed|date=February 2020}} The first keep-right law for [[driving in the United States]] was passed in 1792 and applied to the [[Philadelphia and Lancaster Turnpike]].<ref name="On The Right Side of the Road">{{cite web|url=https://highways.dot.gov/highway-history/general-highway-history/right-side-road|title=On The Right Side of the Road|last=Weingroff|first=Richard|publisher=United States Department of Transportation|access-date=10 January 2014|archive-date=6 September 2023|archive-url=https://web.archive.org/web/20230906042810/https://highways.dot.gov/highway-history/general-highway-history/right-side-road|url-status=live}}</ref> [[Massachusetts]] formalized RHT in 1821.<ref>{{cite web|url=http://archives.lib.state.ma.us/handle/2452/110303|title=An Act Establishing the Law of the Road|publisher=Massachusetts General Court|access-date=14 February 2014|archive-date=18 September 2014|archive-url=https://web.archive.org/web/20140918031615/http://archives.lib.state.ma.us/handle/2452/110303|url-status=live}}</ref> However, the [[National Road]] was LHT until 1850, "long after the rest of the country had settled on the keep-right convention".<ref>{{cite book |last1=Hayes |first1=Brian |title=Infrastructure: a field guide to the industrial landscape |date=2005 |publisher=WW Norton |location=New York |isbn=0-393-05997-9 |page=330}}</ref> Today the United States is RHT except the [[United States Virgin Islands]],<ref>{{cite web|url=http://www.usvitourism.vi/travel_tips|title=Travel Tips &#124; US Virgin Islands|publisher=Usvitourism.vi|access-date=25 April 2012|archive-date=16 March 2011|archive-url=https://web.archive.org/web/20110316035344/http://www.usvitourism.vi/travel_tips|url-status=dead}}</ref> which is LHT like many neighbouring islands.

Some special-purpose vehicles in the United States, like certain postal service trucks, garbage trucks, and parking-enforcement vehicles, are built with the driver's seat on the right for safer and easier access to the curb. A common example is the [[Grumman LLV]], which is used nationwide by the [[United States Postal Service|US Postal Service]] and by [[Canada Post]].