Editing Traffic light (section)

== Variable lane control ==
{{Main|Lane control lights}}

[[File:Lane signals en.svg|thumb|An LED 50-[[watt]] typical lane control signal head]]
[[File:Pont Champlain 2009 02.jpg|alt=Lane control signals installed on the Montréal Old Champlain Bridge.|thumb|Lane control signals installed on the Old Champlain Bridge in [[Montreal|Montréal]], Canada]]
Variable lane control is a form of intelligent transportation systems which involve the use of lane-use control signals, typically on a [[Gantry (transport)|gantry]] above a carriageway. These lights are used in [[Reversible lane|tidal flow]] systems to allow or forbid traffic to use one or more of the available lanes by the use of green lights or arrows (to permit) or by red lights or crosses (to prohibit).<ref name=":3">{{Cite web |title=FHWA – MUTCD – 2003 Edition Revision 1 Chapter 4J |url=https://mutcd.fhwa.dot.gov/htm/2003r1/part4/part4j.htm |access-date=19 December 2021 |website=[[Federal Highway Administration|Federal Highway Administration (FHWA)]]}}</ref> Variable lane control may be in use at toll plazas to indicate open or closed booths; during heavy traffic to facilitate merging traffic from a slip road.<ref name=":3" />

In the US, most notably the Southeastern, there often is a "continuous-flow" lane. This lane is protected by a single, constant-green arrow pointing down at the lane(s) permitting the continuous flow of traffic, without regard to the condition of signals for other lanes or cross streets. Continuous lanes are restricted in that vehicles turning from a side street may not cross over the double white line to enter the continuous lane. No lane changes are permitted to the continuous lane from an adjacent lane or from the continuous lane to an adjacent lane, until the double white line has been passed. Some continuous lanes are protected by a raised curb located between the continuous lane and a normal traffic lane, with white and/or amber reflective paint or tape, prohibiting turning or adjacent traffic from entering the lane.{{cn|date=February 2024}}

Continuous-flow traffic lanes are found only at "T" intersections where there is no side street or driveway entrance on the right side of the main thoroughfare. No pedestrians are permitted to cross the main thoroughfare at intersections with a continuous-flow lane, although crossing at the side street may be permitted. 

Intersections with continuous-flow lanes will be posted with a white regulatory sign approximately {{convert|500|feet|abbr=on}} before the intersection with the phrase, "right lane continuous traffic," or other, similar, wording. If the arrow is extinguished for any reason, whether by malfunction or design, traffic through the continuous lane will revert to the normal traffic pattern for adjacent lanes, except that turning or moving into or out of the restricted lane is still prohibited.{{cn|date=February 2024}}