Editing Traffic congestion (section)

{{Short description|Transport condition characterized by slower speed and high density}}
{{Redirect|Traffic jam}}
{{Use mdy dates|date=October 2023}}
{{Use American English|date=June 2022}} 
[[File:6th Avenue from 49th.jpg|thumb|300px|Congested [[Sixth Avenue]] in [[Midtown Manhattan|Midtown]] [[Manhattan]], [[New York City]], which leads the world in urban automobile traffic congestion,<ref name=NYCCongestion>{{cite web|url=https://www.economist.com/united-states/2024/11/21/congestion-pricing-in-new-york-gets-the-go-ahead-after-all-maybe|title=Congestion pricing in New York gets the go-ahead after all. Maybe|publisher=The Economist|date=November 21, 2024|access-date=November 21, 2024|quote=But traffic is bad most days, with more than 900,000 cars entering Manhattan’s central business district. INRIX, a traffic-data firm, found that New York City leads the world in urban traffic congestion among the cities scored, with the average driver stationary for 101 hours a year.}}</ref> but which has implemented [[Congestion pricing in New York City|congestion pricing]] in January 2025 to address the gridlock]]

'''Traffic congestion''' is a condition in transport that is characterized by slower speeds, longer trip times, and increased vehicular [[Queuing theory|queueing]]. Traffic congestion on urban road networks has increased substantially since the 1950s, resulting in many of the roads becoming obsolete.<ref>{{Cite book|title=Encyclopedia of the City|last=Caves|first=R. W.|publisher=Routledge|year=2004|pages=141}}</ref> When traffic demand is great enough that the interaction between vehicles slows the traffic stream, this results in congestion. While congestion is a possibility for any [[mode of transportation]], this article will focus on automobile congestion on public roads. Mathematically, traffic is modeled as a flow through a fixed point on the route, analogously to [[fluid dynamics]].

As demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in. When vehicles are fully stopped for periods of time, this is known as a '''traffic jam'''<ref>{{Cite book|url=https://books.google.com/books?id=sWiUjVAGTVgC&q=traffic+jam|title=Traffic Flow Dynamics: Data, Models and Simulation|last1=Treiber|first1=Martin|last2=Kesting|first2=Arne|date=October 11, 2012|publisher=Springer Science & Business Media|isbn=978-3-642-32459-8|language=en|access-date=October 29, 2020|archive-date=March 30, 2021|archive-url=https://web.archive.org/web/20210330012623/https://books.google.com/books?id=sWiUjVAGTVgC&q=traffic+jam|url-status=live}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=XikpAQAAMAAJ&q=Traffic+jam%22|title=Traffic Flow Fundamentals|last=May|first=Adolf Darlington|date=1990|publisher=Prentice Hall|isbn=9780139260728|language=en|access-date=October 29, 2020|archive-date=March 30, 2021|archive-url=https://web.archive.org/web/20210330012608/https://books.google.com/books?id=XikpAQAAMAAJ&q=Traffic+jam%22|url-status=live}}</ref> or (informally) a '''traffic snarl-up'''<ref>{{Cite book|url=https://books.google.com/books?id=WVssAQAAMAAJ&q=Journal+article:+%22Traffic+snarl-up%22|title=Hotelier & Caterer: Official Magazine of FEDHASA.|date=July 1993|publisher=Ramsay Son & Parker|language=en|access-date=October 29, 2020|archive-date=March 30, 2021|archive-url=https://web.archive.org/web/20210330012550/https://books.google.com/books?id=WVssAQAAMAAJ&q=Journal+article%3A+%22Traffic+snarl-up%22|url-status=live}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=4o23AAAAIAAJ&q=Journal+article:+%22Traffic+snarl-up%22|title=Eve: The Essence of Africa's New Woman|date=2004|publisher=Oakland Media Services Limited|language=en|access-date=October 29, 2020|archive-date=March 30, 2021|archive-url=https://web.archive.org/web/20210330012550/https://books.google.com/books?id=4o23AAAAIAAJ&q=Journal+article%3A+%22Traffic+snarl-up%22|url-status=live}}</ref> or a '''tailback'''.<ref>{{cite web |title=TAILBACK |url=https://dictionary.cambridge.org/dictionary/english/tailback |publisher=[[Cambridge Dictionary]]}}</ref> Drivers can become frustrated and engage in [[road rage]]. Drivers and driver-focused road planning departments commonly propose to alleviate congestion by adding another lane to the road. This is ineffective: increasing road capacity [[Induced demand|induces more demand]] for driving.