Continuous-flow intersection

A continuous flow intersection (or CFI), also called a crossover displaced left-turn (XDL or DLT), is an alternative design for an at-grade road junction. Vehicles attempting to turn across the opposing direction of traffic (left in countries with right-hand traffic; right in those with left-hand traffic) cross before they enter the intersection. No left turn signal in the intersection is then necessary. Instead, vehicles traveling in both directions can proceed, including through vehicles and those turning right or left, when a generic traffic signal or stop sign permits.

Its design also is promoted as part of the Federal Highway Administration's Every Day Counts initiative which started in 2011.

History Francisco Mier filed in 1987 and received in 1991 U.S. Patent № 5049000 for a fly-over CFI interchange for roads of different grade.US Patent 5049000A. An at-grade intersection version followed. Over 40 have been implemented since 2000. Mier required a licensure fee for users of the design. The patent expired in the United States on 15 October 2003.

This general configuration has appeared in different versions in various places, with the implementation of channelization in the United States since the 1950s, such as the Telegraph Road section of U.S. Route 24 in Michigan at Plymouth Road in Redford Charter Township, Michigan.Telegraph Road, Michigan which was removed in 2019.

Usage +List of places where a CFI is usedCountryState/ProvinceCityRoadsOpening dateCoordinatesNotesAustraliaQueenslandGold CoastSalerno Street, Bundall Road and Ashmore RoadDecember 2017VictoriaMelbournePunt Road, Swan Street and Olympic BoulevardSeptember 2019New South WalesMoore ParkAnzac Parade, Alison Road and Dacey Avenue2017CanadaPrince Edward IslandCharlottetownCharlottetown Perimeter Highway and St. Peters RoadNovember 29, 202046.268692°N 63.114001°WChinaGuangdongShenzhen and Fuhua RoadOctober 7, 201722.537588°N 114.062896°EGermanyHamburgBreitenfelder Straße (Bundesstraße 5) and Tarpenbekstraße (Bundesstraße 433)53.590267°N 9.982989°EMexicoCoahuilaSaltilloPaseo de la Reforma and Periférico und Luis Echeverría25.42739°N 100.969859°WFormer configuration, now a directional interchangeChihuahuaJuárez MunicipalityManuel Gómez Morin Bermúdez aund De La Industria31.70368°N 106.401998°WNuevo LeónGuadalupeBetween Chapultepec, Puesta del Sol and Av Eloy Cavazos25.661967°N 100.258747°WUnited KingdomSwindonA4311 road, Cricklade Road and Thamesdown Drive200351.601158562°N 1.7812545°WUnited StatesNew JerseyCamdenNew Jersey Route 168 at US Route 130Audubon, New JerseyNew Jersey Route 168 at Nicholson Road39.894161°N 75.091435°WNew YorkShirley199640.826443°N 72.881042°WMarylandAccokeekRoutes 210 and 228200038.664126°N 77.016928°WLaurelMD 200 and US 1November 7, 201439.065800°N 76.881176°WLouisianaBaton RougeAirline Highway and Siegen LaneMarch 200630.398914°N 91.054119°WLafayetteUS 167 (Johnston St.) and Camellia Boulevard201030.193744°N 92.058622°WUtahTaylorsvilleBangerter Highway and 5400 South (SR-173)40.652993°N 111.981339°WNo longer existsWest Valley CityBangerter Highway and 4700 South40.667596°N 111.981567°WNo longer existsBangerter Highway and 4100 South40.682132°N 111.981626°WBangerter Highway and 3500 South (SR-171)September 200740.696629°N 111.980869°WBangerter Highway and 3100 South40.703918°N 111.980076°WBangerter Highway and 6200 South (Bennion Boulevard)40.638581°N 111.976637°W No longer exists5400 S (SR-173) and Redwood Road40.653176°N 111.938802°W6200 South (Bennion Boulevard) and Redwood Road40.638574°N 111.938824°WRivertonBangerter Highway and 13400 South40.507803°N 111.982747°WNo longer existsWest JordanBangerter Highway and 7000 South40.623983°N 111.976422°WNo longer existsOremUniversity Parkway and Sandhill RoadMay 22, 201240.275014°N 111.713445°WMississippiNatchezUS 61 and Junkin DriveJanuary 201031.528599°N 91.389213°WOxfordMississippi Highway 6 and West Jackson AvenueApril 29, 2015ColoradoLovelandUS 34 (Eisenhower Boulevard) and Madison Avenue40.407365°N 105.058764°WDurangoUS 160 and US 55037.268540°N 107.884992°WColorado SpringsWoodmen Road and Union BoulevardDecember 201738.933079°N 104.775202°WWheat RidgeWadsworth Boulevard at 38th Avenue and 44th AvenueDecember 9, 202539°46'09.7"N 105°04'53.6"WNorth CarolinaCharlotteNC 16 to Mount Holly-Huntersville RoadOctober 18, 201935.32566°N, 80.94523°WTexasCedar ParkRM 1431 and Ronald Reagan Boulevard/Parmer LaneAugust 2, 201630.534659°N 97.782645°WPflugervilleDessau Road and Pecan Street30.436611°N 97.613889°WSan MarcosLoop 82 (Aquarena Springs Drive) and I-35's southbound-to-northbound Texas U-turn29.893048°N 97.913367°WState Highway 80 (Hopkins Street), I-35's frontage roads and I-35's Texas U-turns29.882639°N 97.921915°WSan AntonioBandera Road and Loop 1604April 28, 201929.553655°N 98.667302°WGeorgiaDawsonvilleSR 400 and SR 53May 15, 201734.363385°N 84.036474°WIndianaIndianapolisUS 31 and Thompson RoadOctober 8, 202239.693213°N 86.148812°WOhio Township (Warrick County)IN 66 and Epworth RoadAugust 20, 2024 37.976790°N 87.441226°W EvansvilleIN 66 and Stockwell RoadJune 18, 2025 37.976675°N 87.502408°WHybrid design with one displaced left turn and a Michigan left as the other turn.IN 66 and Burkhardt RoadAugust 17, 2026 (westbound) 37.976625°N 87.474061°WCurrently only open to westbound turns. The eastbound turn lanes are scheduled to open in fall 2026.IN 66 and Eagle Crest/Cross Pointe BoulevardsAugust 17, 2026 (westbound) 37.976743°N 87.462698°WCurrently only open to westbound turns. The eastbound turn lanes are scheduled to open in fall 2026.OhioAnderson TownshipBeechmont Avenue (State Route 125) and Five Mile RoadMay 19, 201739°4′22″N 84°21′7″WMiami Township (Montgomery County)SR 741 and Miamisburg-Springboro Road/Austin Boulevard200939.596709°N 84.229029°WVirginiaNorfolkMilitary Highway onto Northampton Boulevard and Princess Anne RoadJuly 28, 201836.874804°N 76.210739°WFloridaFort MyersState Road 82 to Daniels Parkway (west) and Gunnery Road (east)July 9, 201926.581661°N 81.713761°WKansasOlatheOld 56 Highway to Lone Elm RoadJune 2021MissouriFentonHighway 30 and Summit Drive/Gravois Bluffs BoulevardOctober 200738.504276°N 90.456995°W

Operational details Part of the delay at a typical high-volume right-hand traffic intersection is to accommodate left-turns; through-traffic must wait for the traffic turning left because it crosses the path of the through traffic. The continuous flow intersection moves the left-turn conflict out of the intersection and synchronizes it with the signal cycle of the intersecting road.

In the adjacent diagram, while the left/right traffic flows through the main intersection, the left-turn traffic crosses to the opposite side of the oncoming traffic a few hundred feet away. Doing this removes the crossing conflict. When the north/south through traffic is allowed through the main intersection, the north/south left-turn lanes are also allowed through the intersections as their paths are no longer crossing. All traffic flow is controlled by traffic signals as at a regular intersection.

The Louisiana DOTD article on the Baton Rouge CFI includes a particularly informative diagram of that intersection.

To reduce confusion regarding the left-turn lane, the left-turn lane and the straight-through lanes are usually separated by a concrete barrier or traffic island. This diagram shows the straight-through lanes offset by one lane through the intersection and are guided by lines painted through the intersection. But this is just a sample configuration; the lanes may be offset by more lanes or none at all.

Nonetheless, due to the provision of traffic between two directions of opposing traffic, some motorists tend to maintain an ongoing criticism of the intersection. Additionally, as in the case of the half-CFI in Accokeek, the offset left-turn traffic reenters the main traffic stream via a half-signal, requiring motorists to merge from a stop condition onto the higher-speed mainline. Motorists sometimes cite discomfort due to the speed differential, a known cause of accidents, though conflicts can be reduced through the provision of an adequate acceleration lane and merge area. The Accokeek, Maryland CFI also has notable inequalities in traffic flow depending upon the direction of travel.

This type of intersection can require a significant amount of right-of-way to implement (dependent upon the configuration), which is why the technique is not frequently used in urban areas. However, the amount of right-of-way necessary for construction and final operation is still typically less than that of an interchange. Additionally, as there is no grade separation involved, costs are considerably less than that of an interchange alternative.

Case studies The redesign of the Redwood Road/6200 South intersection in Taylorsville, Utah cut emissions of carbon dioxide by 19 tons (17 tonnes) per year.FHWA: DLT Case Study – Redwood Road at 6200 South in Taylorsville (Utah), published July 31, 2014 Compared to the previous design, the redesign of the Bangerter Highway/3500 South intersection saves minutes of travel time per vehicle and of fuel per year, and has 60% fewer accidents nearby; it also cost $20 million to $40 million less in construction costs than a grade-separated alternative.FHWA: DLT Case Study – Bangerter Highway in Salt Lake County (Utah), published July 31, 2014

Parallel-flow intersection A parallel-flow intersection (PFI) is a variant similar to the CFI, patented in 2006. It arranges the left-turning traffic in a different manner; it is not displaced, instead turning left closer to the intersection onto a parallel roadway, to the left of oncoming traffic.Federal Highway Administration: Alternative Intersections/Interchanges: Informational Report (AIIR), Publication Number: FHWA-HRT-09-060, April 2010 This was first used in New Jersey at the junction of New Jersey Route 168 and US Highway 130, between Haddon Township and Camden ().

Continuous-flow intersection

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