Editing Traffic congestion (section)

===Supply and demand===
{{See also|Transportation demand management}}
[[File:Autoroute M25.jpg|thumb|Widening works under way on the [[M25 motorway]] surrounding [[London, England]] to increase the number of lanes]]
[[File:Noratrun.jpg|thumb|right|During [[rush hour]], right turns onto the side street shown here are prohibited in order to prevent [[rat running]].]]
Congestion can be reduced by either increasing road capacity (supply), or by reducing traffic (demand). Capacity can be increased in a number of ways, but needs to take account of [[induced demand|latent demand]] otherwise it may be used more strongly than anticipated. Critics of the approach of adding capacity have compared it to "fighting [[obesity]] by letting out your belt" (inducing demand that did not exist before). For example, when new lanes are created, households with a second car that used to be parked most of the time may begin to use this second car for commuting.<ref>{{Cite web |url=http://www.janeholtzkay.com/Articles/cleancar.html |title=Dreaming of a Clean Car? |archive-url=https://web.archive.org/web/20080518004530/http://www.janeholtzkay.com/Articles/cleancar.html |archive-date=May 18, 2008 |author-link=Jane Holtz Kay|last=Kay |first=Jane Holtz}}</ref><ref>{{Cite web |url=http://naioptb.org/news/2005mayors.asp |title=2005 Mayors Luncheon |archive-url=https://web.archive.org/web/20070927223155/http://naioptb.org/news/2005mayors.asp |archive-date=September 27, 2007 |work=the NAIOP website, [[Tampa Bay]], United States}}</ref> Reducing road capacity has in turn been attacked as removing free choice as well as increasing travel costs and times, placing an especially high burden on the low income residents who must commute to work.{{citation needed|date=October 2017}}

Increased supply can include:
* Adding more capacity at bottlenecks (such as by adding more lanes at the expense of [[hard shoulder]]s or safety zones, or by removing local obstacles like bridge supports and widening tunnels)
* Adding more capacity over the whole of a route (generally by adding more lanes)
* Creating new routes
* Traffic management improvements (see separate section below)

Reduction of demand can include:
* [[Parking|Parking restrictions]], making motor vehicle use less attractive by increasing the monetary and non-monetary costs of parking, introducing greater competition for limited city or road space.<ref>{{Cite journal | author = Hermann Knoflacher | year = 2006 | title = A new way to organize parking: the key to a successful sustainable transport system for the future | journal = Environment and Urbanization | volume = 18 | issue = 2 | pages = 387–400 | doi = 10.1177/0956247806069621 | bibcode = 2006EnUrb..18..387K | s2cid = 153752634 | author-link = Hermann Knoflacher| doi-access = free }}
</ref> Most transport planning experts agree that [[free parking]] distorts the market in favor of car travel, exacerbating congestion.<ref>
{{Cite book |last= Shoup |first= Donald C. |author-link = Donald Shoup|title= The High Cost of Free Parking |year=2005|publisher=American Planning Association |isbn=978-1-884829-98-7}}
</ref><ref>{{Cite book| last= Knoflacher| first= Hermann| author-link= Hermann Knoflacher| title= Stehzeuge. Der Stau ist kein Verkehrsproblem.| orig-year= 2001| publisher= Böhlau| location= Vienna| language= de| isbn= 978-3-205-98988-2| date=January 2001}}</ref>
* [[Park and ride]] facilities allowing parking at a distance and allowing continuation by [[public transport]] or [[car pool|ride sharing]]. Park-and-ride [[car park]]s are commonly found at [[metro station]]s, freeway entrances in suburban areas, and at the edge of smaller cities.
* Reduction of road capacity to force traffic onto other [[modal share|travel modes]]. Methods include [[traffic calming]] and the [[shared space]] concept.
* [[Road pricing]], charging money for access onto a road/specific area at certain times, congestion levels or for certain road users
** "Cap and trade", in which only licensed cars are allowed on the roads.<ref>
{{Cite journal
 | last = Goddard
 | first = Haynes
 |date=July 1997
 | title =  Using Tradeable Permits to Achieve Sustainability in the World's Large Cities
 | journal = Environmental and Resource Economics
 | volume = 10
 | issue = 1
 | pages = 63–99
 | doi = 10.1023/A:1026444113237
 | s2cid = 154186781
 }}
</ref> A limited quota of car licenses are issued each year and traded in a [[free market]] fashion. This guarantees that the number of cars does not exceed road capacity while avoiding the negative effects of [[economic shortage|shortages]] normally associated with quotas. However, since demand for cars tends to be inelastic, the result are exorbitant purchase prices for the licenses, pricing out the lower levels of society, as seen Singapore's [[Certificate of Entitlement]] scheme.<ref name="toh">{{Cite web |url=http://www.findarticles.com/p/articles/mi_m1038/is_n2_v37/ai_15419789 |title=The high cost of motoring in Singapore |last=Toh |first=Rex S. |work=Business Horizons |date=March–April 1994 |access-date=October 2, 2017 |archive-date=October 17, 2015 |archive-url=https://web.archive.org/web/20151017130544/http://www.findarticles.com/p/articles/mi_m1038/is_n2_v37/ai_15419789 |url-status=dead }}</ref>
** [[Congestion pricing]], including:
*** Congestion zone charges, in which entry via car to a certain area, such as the inner part of a city, requires payment. Enforcement may be a physical boundary (e.g., toll stations) or it may be virtual, via spot checks or cameras. Major examples include [[congestion pricing in New York City]]; [[Singapore]]'s [[electronic road pricing]]; the [[London congestion charge]]; and the [[Stockholm congestion tax]].
*** Fixed (the same at all times of day), variable (higher at peak times), or dynamic (higher during actual congestion) [[toll road]]s, [[toll bridge]]s, [[toll tunnel]]s, and toll lanes
* [[Managed lane]]s
** [[High-occupancy toll lane]]s
** [[Reversible lane]]s
** [[High-occupancy vehicle lane]]s
** [[Bus lane]]s
** [[Truck lane restriction]]s and [[climbing lane]]s, to allow faster vehicles to move unimpeded
** Allowing driving on highway shoulders at peak times
* [[Road space rationing]], where regulatory restrictions prevent certain types of vehicles from driving under certain circumstances or in certain areas.
** [[Vehicle registration plate|Number plate]] restrictions based on days of the week, as practiced in several large cities in the world, such as [[Athens]],<ref>
{{cite web|url=http://www.leda.ils.nrw.de/database/measures/meas0205.htm|title=LEDA Measure: License plate based traffic restrictions, Athens, Greece|publisher=LEDA database|access-date=April 9, 2008|url-status=dead|archive-url=https://web.archive.org/web/20080227030125/http://www.leda.ils.nrw.de/database/measures/meas0205.htm|archive-date=February 27, 2008}}
</ref> [[Mexico City]], [[Manila]], and São Paulo.<ref name=konsult>{{cite web |url         = http://www.elseviersocialsciences.com/transport/konsult/private/level2/instruments/instrument009/l2_009a.htm |title       = Regulatory restrictions |work        = KonSULT, the Knowledgebase on Sustainable Urban Land use and Transport |publisher   = Institute for Transport Studies, University of Leeds |url-status     = dead |archive-url  = https://web.archive.org/web/20040825080318/http://www.elseviersocialsciences.com/transport/konsult/private/level2/instruments/instrument009/l2_009a.htm |archive-date = August 25, 2004
}}
</ref> In effect, such cities are banning a different part of the automobile fleet from roads each day of the week. Mainly introduced to combat [[smog]], these measures also reduce congestion. A weakness of this method is that richer drivers can purchase a second or third car to circumvent the ban.{{Citation needed|date=September 2007}}
** [[License|Permits]], where only certain types of vehicles (such as residents) are permitted to enter a certain area, and other types (such as through-traffic) are banned.<ref name=konsult/> For example, [[Bertrand Delanoë]], the mayor of [[Paris]], has proposed to impose a complete ban on motor vehicles in the city's inner districts, with exemptions only for residents, businesses, and the disabled.<ref>{{Cite news | first = Jon | last = Henley | title = Paris drive to cut traffic in centre by 75% | url = https://www.theguardian.com/world/2005/mar/15/france.jonhenley | work = [[The Guardian]] | location = London | date = March 15, 2005 | archive-date = September 18, 2014 | archive-url = https://web.archive.org/web/20140918025826/http://www.theguardian.com/world/2005/mar/15/france.jonhenley | url-status = live }}</ref>
[[File:TrafficJamBikeLane.jpg|thumb|Bike lane constructed in areas of low space to encourage use of human-sized transportation]]
* [[Policy]] approaches, which usually attempt to provide either strategic alternatives or which encourage greater usage of existing alternatives through promotion, subsidies or restrictions.
** Incentives to use [[public transport]], increasing modal shares. This can be achieved through infrastructure investment, subsidies, transport [[Intermodal passenger transport|integration]], pricing strategies that decrease the [[marginal cost]]/[[fixed cost]] ratios,<ref name=simon>
{{Cite journal  | first = Hermann  | last = Simon |author2=Robert J Dolan  | title = Price Customization  | publisher = American Marketing Association  | journal = Marketing Management  | volume = 7  | issue = 3}}</ref><ref name=link>{{Cite journal  | first = Heike  | last = Link  | title =  PEP-A Yield-Management Scheme for Rail Passenger Fares in Germany  | journal = Japan Railway & Transport Review  | volume = 38  |date=March 2004  | page = 54}}</ref> improved [[Public transport timetable|timetabling]] and greater priority for buses to reduce journey time e.g. [[bus lanes]] or [[bus rapid transit]] .<ref>{{Cite journal| last = Andersen | first = Bjørn |date=January 1993 | title = A survey of the Swiss public transport system and policy | journal = Transport Reviews | volume = 13 | issue = 1 | pages = 61–81 | doi = 10.1080/01441649308716835 }}
</ref><ref>{{cite web|url= http://eprints.whiterose.ac.uk/2058/|title= The philosophy and practice of Taktfahrplan: a case-study of the East Coast Main Line| first= Adrian | last=May|date= March 16, 2007|format= Working Paper|work= Working Paper 579|publisher= Institute of Transport Studies, University of Leeds, Leeds, UK|archive-date= December 10, 2007|archive-url= https://web.archive.org/web/20071210001239/http://eprints.whiterose.ac.uk/2058/|url-status= live}}</ref>
** [[Utility cycling|Cycling]] promotion through legislation, cycle facilities, subsidies, and awareness campaigns.<ref>{{Cite journal | last1 = Ogilvie | first1 = David | first2=Matt | last2=Egan |author3=Val Hamilton |author4=Mark Petticrew  | date = September 22, 2004 | title = Promoting walking and cycling as an alternative to using cars: systematic review | journal = [[British Medical Journal]] | volume = 329 | issue = 7469 | page = 763 | doi = 10.1136/bmj.38216.714560.55 | pmid = 15385407 | pmc = 520994 }}
</ref> [[Cycling in the Netherlands|The Netherlands has been pursuing cycle friendly policies]] for decades, and around a quarter of their commuting is done by bicycle.<ref>{{Cite journal | last1 = Rietveld | first1 = Piet | first2=Vanessa | last2=Daniel  |date=August 2004 | title = Determinants of bicycle use: do municipal policies matter? | journal = Transportation Research Part A: Policy and Practice | volume = 38| issue = 7 | pages = 531–550 | doi = 10.1016/j.tra.2004.05.003 | author-link = Piet Rietveld | doi-access = free | bibcode = 2004TRPA...38..531R }}</ref><ref>{{cite web |url=http://www.fietsberaad.nl/library/repository/bestanden/Cycling%20in%20the%20Netherlands%20VenW.pdf |title= Cycling in the Netherlands |publisher    = [[Rijkswaterstaat]] (Dutch Ministry of Transport, Public Works and Water Management) |archive-url=https://web.archive.org/web/20080528100652/http://www.fietsberaad.nl/library/repository/bestanden/Cycling%20in%20the%20Netherlands%20VenW.pdf |archive-date = May 28, 2008 |url-status     = dead}}</ref>
** Promotion of more flexible work place practices. For example, a flexible workplaces pilot was undertaken in Brisbane, Australia during 2009 to test the applicability of a voluntary travel behavior change program to achieve transport system outcomes, particularly as they related to managing congestion, either through mode shift or peak spreading. During the one-month Pilot, amongst almost 900 Brisbane CBD workers across 20 private and public sector organizations, shifts of more than 30% out of the morning and afternoon peak travel was recorded.<ref>Marinelli, P. A. Cleary, N. Worthington Eyre, H. and Doonan, K. 2010. Flexible Workplaces: Achieving the worker's paradise and transport planner's dream in Brisbane, Proceedings of the 33rd Australasian Transport Research Forum, September 29-October 1, 2010, Canberra.</ref>
** [[Remote work]] encouraged through legislation and subsidies.<ref>{{cite web |url=http://www.discovery.org/scripts/viewDB/index.php?command=view&program=DI%20Main%20Page%20-%20News&id=4235 |title=Slow But Steady "Telework Revolution" Eyed |author=Matt Rosenberg|publisher=Cascadia Prospectus|date=September 26, 2007|access-date=October 7, 2007|archive-date=October 27, 2007|archive-url=https://web.archive.org/web/20071027153140/http://www.discovery.org/scripts/viewDB/index.php?command=view&program=DI%20Main%20Page%20-%20News&id=4235|url-status=live}}</ref>
** [[Online shopping]] promotion,<ref name=rac2050>
{{cite web
 | title = Motoring Towards 2050 – Roads and Reality
 | url = http://www.racfoundation.org/index.php?option=com_content&task=view&id=535&Itemid=31
 | publisher = [[RAC foundation]]
 | url-status = dead
 | archive-url = https://web.archive.org/web/20090120175029/http://www.racfoundation.org/index.php?option=com_content&task=view&id=535&Itemid=31
 | archive-date = January 20, 2009
 }}
</ref><ref name=dft>{{cite web
 | title = Smarter Choices – Changing the way we travel
 | date = June 24, 2005
 | url = http://www.dft.gov.uk/pgr/sustainable/smarterchoices/ctwwt/
 | publisher = [[Department for Transport]]
 | access-date = April 21, 2008
 | archive-date = April 8, 2008
 | archive-url = https://web.archive.org/web/20080408055546/http://www.dft.gov.uk/pgr/sustainable/smarterchoices/ctwwt/
 | url-status = live
 }}</ref> potentially with [[Packstation|automated delivery booths]] helping to solve the [[Last mile (transportation)|last mile problem]] and reduce shopping trips made by car.{{citation needed|date=April 2021}}