Editing Traffic congestion (section)

===Improving road infrastructure===
[[File:Grnfld Ramp.jpg|thumb|Metered ramp on [[Interstate 894|I-894]] in [[Milwaukee, Wisconsin]], U.S. The queue of cars waiting at the red light can be seen on the upper portion of the picture.]]
[[File:A38(M) Aston Expressway.jpg|thumb|The [[A38(M) motorway|A38M Aston Expressway]] in [[Aston]], towards central [[Birmingham]] - the lanes are controlled via the overhead gantries, which reverse the flow of one lane (making 4 in one direction, 2 in the other and a central buffer lane) during peak times accordingly.]]
[[File:404HOV lane.png|thumb|upright|The HOV lanes in [[Highway 404]] in [[Southern Ontario]] are separated by a stripped buffer zone that breaks occasionally to allow vehicles to enter and exit the HOV lane.]]

* Increasing road capacity is standard response to congestion, perhaps by widening an existing road or adding a new road, bridge or tunnel. However, this has been shown to result in attracting more traffic, otherwise known as [[induced demand]]. The result can be greater congestion on the expanded artery itself or on auxiliary roads.<ref name="Schneider 2018">{{cite web |last1=Schneider |first1=Benjamin |title=CityLab University: Induced Demand |website=[[Bloomberg News]] |url=https://www.bloomberg.com/news/articles/2018-09-06/traffic-jam-blame-induced-demand |access-date=January 18, 2022 |date=September 6, 2018}}</ref> In a similar vein, [[Braess's paradox]] shows that adding road capacity might make congestion worse, even if demand does not increase. In his paper, "The Law of Peak Hour Express Way Congestion", published in 1962, Anthony Downs formulated this phenomenon as a "law": "on urban commuter expressways, peak-hour traffic congestion rises to meet maximum capacity."{{sfn |Downs |1962 |p=393}}
* [[Junction (road)|Junction]] improvements
** [[Grade separation]], using bridges (or, less often, tunnels) freeing movements from having to stop for other crossing movements
** [[Ramp meter|Ramp signaling]], 'drip-feeding' merging traffic via [[traffic signal]]s onto a congested motorway-type roadway
** Reducing junctions
*** [[Local-express lanes]], providing through lanes that bypass junction on-ramp and off-ramp zones
*** [[Limited-access road]], roads that limit the type and amounts of [[driveway]]s along their lengths
* [[Reversible lane]]s, where certain sections of highway operate in the opposite direction on different times of the day(s) of the week, to match asymmetric demand. These pose a potential for collisions, if drivers do not notice the change in direction indicators. This may be controlled by [[variable-message sign]]s or by movable physical separation
* Separate lanes for specific user groups (usually with the goal of higher people throughput with fewer vehicles)
** [[Bus lanes]] as part of a [[Bus rapid transit|busway system]]
** [[High-occupancy toll lane|Express toll lanes]]
** [[High-occupancy vehicle lane|HOV lanes]], for vehicles with at least three (sometimes at least two) riders, intended to encourage [[carpool]]ing
*** [[Slugging]], impromptu carpooling at HOV access points, on a [[hitchhiking]] or payment basis
*** [[Market economy|Market-based]] carpooling with pre-negotiated financial incentives for the driver