A continuous flow intersection (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 right-hand drive jurisdictions; right in left-hand drive jurisdictions) 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/stop sign permits. Its design also is promoted as part of the Federal Highway Administration's

Every Day Counts initiative The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...

which started in 2011.

History

A fly-over designed CFI interchange (separated grade) was invented by Francisco Mier. An intersection (at-grade) variant followed. Over 40 have been implemented since 2000. Mier patented his design and required a fee to obtain a license to 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 US Highway 24 (US 24) is a United States Numbered Highway that runs from Minturn, Colorado, to Independence Township, Michigan. In Michigan, it is also known as Telegraph Road and runs for as a major north–south state trunkline highway from ...

at Plymouth Road in

Redford Charter Township, Michigan Redford, officially the Charter Township of Redford, is a charter township in Wayne County in the U.S. state of Michigan. The township shares its eastern border with the city of Detroit. The population was 49,504 at the 2020 census. History S ...

Usage

Australia

* Salerno Street, Bundall Road and Ashmore Road intersection, in Gold Coast, Queensland, has Australia's first continuous-flow intersection. The intersection was upgraded as Continuous-flow in December 2017. * Hoddle Street, a major north/south arterial road near Melbourne’s Central Business District (known as the “

Hoddle Grid Hoddle Grid is the contemporary name given to the approximately grid of streets that form the Melbourne central business district, Australia. Bounded by Flinders Street, Spring Street, La Trobe Street, and Spencer Street, it lies at an ang ...

”) has suffered major congestion for several years. The state of Victoria announced in their budget for 2016/7 that several intersections will be converted to continuous flow intersections. Various right turns along Hoddle Street have now been replaced with U-turns, which then require turning left at the desired street. *Intersection of Anzac Parade, Alison Road and Dacey Avenue in

Moore Park, New South Wales Moore Park is a small suburb located southeast of the Sydney central business district, in the eastern suburbs of Sydney, in the state of New South Wales, Australia. It is part of local government area of the City of Sydney. Moore Park is ...

was proposed in 2017 to be converted to a continuous-flow intersection.

Canada

* Intersection of the Charlottetown Perimeter Highway with St. Peters Road in

Charlottetown, Prince Edward Island Charlottetown is the capital and largest city of the Canadian province of Prince Edward Island, and the county seat of Queens County. Named after Queen Charlotte, Charlottetown was an unincorporated town until it was incorporated as a city in ...

opened on November 29, 2020.

China

* Intersection of Caitian Road and Fuhua Road in Futian, Shenzhen. In operation since 7 October 2017.

Germany

* Single-leg CFI at Eppendorfer Park in

Hamburg Hamburg (, ; nds, label=Hamburg German, Low Saxon, Hamborg ), officially the Free and Hanseatic City of Hamburg (german: Freie und Hansestadt Hamburg; nds, label=Low Saxon, Friee un Hansestadt Hamborg),. is the List of cities in Germany by popul ...

between Breitenfelder Straße ( Bundesstraße 5) and Tarpenbekstraße (

Bundesstraße 433 The Bundesstraße 433 is a Bundesstraße (federal road) in Hamburg. Path The road begins in Eppendorf, Hamburg, Hamburg-Eppendorf at the intersection with the Bundesstraße 5, B 5 and continues via the Tarpenbekstraße, Rosenbrook, Alsterkrugch ...

Mexico

* Between Chapultepec, Puesta del Sol and Av Eloy Cavazos,

Guadalupe, Nuevo León Guadalupe is a city and surrounding municipality located in the state of Nuevo León, in northern Mexico. It is part of the Greater Monterrey Metropolitan area. The municipality of Guadalupe, which lies adjacent to the east side of Monterrey, a ...

, * Manuel Gómez Morin Bermúdez aund De La Industria, Bermúdez,

Juárez Municipality, Chihuahua Juárez is one of the 67 municipalities of Chihuahua, in northern Mexico. The municipal seat lies at Ciudad Juárez. The municipality covers an area of . In the 2010 INEGI Census, the municipality reported a total population of 1,332,131, of ...

, * Paseo de la Reforma / Periférico und Luis Echeverría,

Saltillo Saltillo () is the capital and largest city of the northeastern Mexican state of Coahuila and is also the municipal seat of the municipality of the same name. Mexico City, Monterrey, and Saltillo are all connected by a major railroad and highwa ...

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

United Kingdom

* On A4311 road, Cricklade Road and Thamesdown Drive in Swindon, opened in 2003,

United States

Continuous-flow-intersection-cfi-4arm-2way-ani

Listed in chronological order: # Haddon Township, Audubon and

Audubon Park, New Jersey Audubon Park is a Borough (New Jersey), borough in Camden County, New Jersey, Camden County, New Jersey, United States. As of the 2010 United States census, the borough's population was 1,023,New Jersey Route 168 at Nicholson Road, is a hybrid one-leg continuous flow intersection that also employs a

jughandle A jughandle is a type of ramp or slip road that changes the way traffic turns left at an at-grade intersection (in a country where traffic drives on the right). Instead of a standard left turn being made from the left lane, left-turning traffi ...

. #

Shirley, New York Shirley is a hamlet (and census-designated place) in Suffolk County, New York, United States. At the 2010 census, the population of Shirley was 27,854. Shirley is the western terminus of Atlantic Crossing 1, a major submarine telecommunications ...

, opened in 1996, at the entrance to

Dowling College Dowling College was a private college on Long Island, New York. It was established in 1968 and had its main campus located in Oakdale, New York on the site of William K. Vanderbilt's mansion Idle Hour. Dowling also included a campus in Shirl ...

. # Accokeek, Maryland, opened in 2000, at the intersection of Routes 210 and

228 Year 228 ( CCXXVIII) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Modestus and Maecius (or, less frequently, year 981 '' Ab urbe con ...

. This is an example of a CFI-T, which is a

T intersection A three-way junction (or three-way intersection) is a type of road intersection with three arms. A Y junction (or Y intersection) generally has three arms of equal size coming at an acute or obtuse angle to each other; while a T junction (or T ...

containing one CFI leg. This junction also has characteristics of a continuous green T (or seagull) intersection. While neither of the routes is

grade-separated In civil engineering (more specifically highway engineering), grade separation is a method of aligning a junction of two or more surface transport axes at different heights (grades) so that they will not disrupt the traffic flow on other t ...

, southbound through traffic on Route 210 is free-flowing. #

Baton Rouge, Louisiana Baton Rouge ( ; ) is a city in and the capital of the U.S. state of Louisiana. Located the eastern bank of the Mississippi River, it is the parish seat of East Baton Rouge Parish, Louisiana's most populous parish—the equivalent of count ...

, opened in March 2006, at the intersection of

Airline Highway Airline Highway is a divided highway in the U.S. state of Louisiana, built in stages between 1925 and 1953 to bypass the older Jefferson Highway. It runs , carrying U.S. Highway 61 from New Orleans northwest to Baton Rouge and U.S. Highway ...

and Siegen Lane. # Along Utah State Route 154 (Bangerter Highway) at ## 5400 South (SR-173) in Taylorsville, ## 4700 South in Taylorsville and West Valley City, ## 4100 South in West Valley City, ## 3500 South (SR-171) in West Valley City, opened in September 2007, ## 3100 South in West Valley City, # Fenton, Missouri, opened October 2007, at the intersection of Highway 30 and Summit Drive/Gravois Bluffs Boulevard. # Miami Township, Montgomery County, Ohio, a two-leg CFI constructed in the spring of 2009, at the intersection of SR 741 and Miamisburg-Springboro Road/Austin Boulevard. #

Salt Lake County, Utah Salt Lake County is located in the U.S. state of Utah. As of the 2020 United States Census, the population was 1,185,238, making it the most populous county in Utah. Its county seat and largest city is Salt Lake City, the state capital. The co ...

, in October 2009, the

Utah Department of Transportation The Utah Department of Transportation (UDOT) is an agency of the state government of Utah, United States; it is usually referred to by its initials UDOT (pronounced "you-dot"). UDOT is charged with maintaining the more than of roadway that co ...

announced plans for five more continuous flow intersections along Bangerter Highway and Redwood Road (SR-68). As of March 11, 2011, four of them were in use. ## 13400 South and Bangerter Highway in Riverton, ## 7000 South and Bangerter Highway in

West Jordan West Jordan is a city in Salt Lake County, Utah, United States. It is a suburb of Salt Lake City and has a mixed economy. According to the 2020 Census, the city had a population of 116,961, placing it as the third most populous in the state. T ...

, ## 6200 South (Bennion Boulevard) and Bangerter Highway in Taylorsville, ## W 5400 S (SR-173) and Redwood Road in Taylorsville, ## 6200 South (Bennion Boulevard) and Redwood Road in Taylorsville, #

Natchez, Mississippi Natchez ( ) is the county seat of and only city in Adams County, Mississippi, United States. Natchez has a total population of 14,520 (as of the 2020 census). Located on the Mississippi River across from Vidalia in Concordia Parish, Louisiana, ...

, opened January 2010 at the intersection of

US 61 U.S. Route 61 or U.S. Highway 61 (U.S. 61) is a major United States highway that extends between New Orleans, Louisiana and the city of Wyoming, Minnesota. The highway generally follows the course of the Mississippi River and is designate ...

and Junkin Drive, designed by ABMB Engineers and constructed by MDOT. #

Lafayette, Louisiana Lafayette (, ) is a city in the U.S. state of Louisiana, and the most populous city and parish seat of Lafayette Parish, located along the Vermilion River. It is Louisiana's fourth largest incorporated municipality by population and the 234 ...

, ground broke January 2010 at the intersection of US 167 (Johnston St.) and Camellia Boulevard. Estimated cost of $3.5 million. #

Loveland, Colorado The City of Loveland is the home rule municipality that is the second most populous municipality in Larimer County, Colorado, United States. Loveland is situated north of the Colorado State Capitol in Denver and is the 14th most populous city ...

, ground broke June 2010 at the intersection of US 34 (Eisenhower Boulevard) and Madison Avenue. Estimated cost of $4 million. #

Orem, Utah Orem is a city in Utah County, Utah, United States, in the northern part of the state. It is adjacent to Provo, Lindon, and Vineyard and is approximately south of Salt Lake City. Orem is one of the principal cities of the Provo-Orem, Utah Me ...

, opened May 22, 2012 at the intersection of University Parkway and Sandhill Road, as part of the

Interstate 15 Interstate 15 (I-15) is a major Interstate Highway in the western United States, running through Southern California and the Intermountain West. I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Cana ...

CORE project. #

Durango, Colorado Durango is a home rule municipality that is the county seat and the most populous municipality of La Plata County, Colorado, United States. The city population was 19,071 at the 2020 United States Census. Durango is the home of Fort Lewis ...

, at the intersection of US 160 and US 550. Estimated cost of $6.1 million. #

Laurel, Maryland Laurel is a city in Maryland, United States, located midway between Washington and Baltimore on the banks of the Patuxent River. While the city limits are entirely in northern Prince George's County, outlying developments extend into Anne Arun ...

, at the intersection of MD 200 and US 1; opened November 7, 2014. This is a CFI-T, with a similar configuration as that for Accokeek, Maryland, listed above. Northbound through traffic on US 1 is free-flowing. #

Oxford, Mississippi Oxford is a city and college town in the U.S. state of Mississippi. Oxford lies 75 miles (121 km) south-southeast of Memphis, Tennessee, Memphis, Tennessee, and is the county seat of Lafayette County, Mississippi, Lafayette County. Founded i ...

, at the intersection of

Mississippi Highway 6 Mississippi Highway 6 (MS 6) runs east–west from MS 161 in Lyon, east to MS 25 near Amory. It travels approximately , serving Coahoma, Quitman, Panola, Lafayette, Pontotoc, Lee, and Monroe Counties. West of Tupelo, it is co ...

and West Jackson Avenue; opened April 29, 2015. #

Cedar Park, Texas Cedar Park is a city and a major suburb of Austin in the state of Texas, approximately to the north-west of the center of Austin. According to the 2020 U.S. Census, the city's population was 77,595. History Before the arrival of European sett ...

, opened on August 2, 2016 at the intersection of RM 1431 and Ronald Reagan Boulevard/ Parmer Lane. The project, which included widening nearby roads from four to six lanes, cost $18.2 million. # San Marcos, Texas, two CFIs were constructed. One is a single-leg CFI at the intersection of Loop 82 (Aquarena Springs Drive),

Interstate 35 Interstate 35 (I-35) is a major Interstate Highway in the central United States. As with most primary Interstates that end in a five, it is a major cross-country, north–south route. It stretches from Laredo, Texas, near the Mexican border ...

's southbound

frontage road A frontage road (also known as an access road, outer road, service road, feeder road, or parallel road) is a local road running parallel to a higher-speed, limited-access road. A frontage road is often used to provide access to private drive ...

and I-35's southbound-to-northbound Texas U-turn (). The other, a two-leg CFI, is at the intersection of State Highway 80 (Hopkins Street), I-35's frontage roads and I-35's Texas U-turns (). In both intersections, the displaced left turn lanes merge with the Texas U-turn lanes. The estimated cost for both CFIs is $4.7 million. # Dawsonville, Georgia, opened May 15, 2017 at the intersection of SR 400 and SR 53. This is a two-leg CFI, estimated by the

Georgia Department of Transportation The Georgia Department of Transportation (GDOT) is the organization in charge of developing and maintaining all state and federal roadways in the U.S. state of Georgia. In addition to highways, the department also has a limited role in developi ...

in 2010 to cost about $14 million. # Anderson Township, Hamilton County, Ohio, two-leg CFI opened May 19, 2017, at the intersection of Beechmont Avenue (State Route 125) and Five Mile Road. # Colorado Springs, Colorado, two-leg CFI opened in December 2017 at the intersection of Woodmen Road and Union Boulevard. #

Norfolk, Virginia Norfolk ( ) is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia in the United States. Incorporated in 1705, it had a population of 238,005 at the 2020 United States Census, 2020 cen ...

, two-leg CFI, left turns from Military Highway onto Northampton Boulevard and Princess Anne Road opened July 28, 2018. #

San Antonio, Texas ("Cradle of Freedom") , image_map = , mapsize = 220px , map_caption = Interactive map of San Antonio , subdivision_type = Country , subdivision_name = United States , subdivision_type1= State , subdivision_name1 = Texas , subdivision_t ...

, two-leg CFI, left turns from Bandera Road to

Loop 1604 Loop 1604 is the outer highway loop encircling San Antonio, Texas, spanning approximately . Originally constructed as a two-lane highway, the northern segment of the route, from US 90 in western San Antonio to Kitty Hawk Road in northeaster ...

opened on April 28, 2019. Like the ones in San Marcos, the displaced left turn lanes merge with the Texas U-turn lanes. #

Fort Myers, Florida Fort Myers (or Ft. Myers) is a city in southwestern Florida and the county seat and commercial center of Lee County, Florida, United States. The Census Bureau's Population Estimates Program calculated that the city's population was 92,245 in 2 ...

, two-leg CFI, left turns from State Road 82 to Daniels Parkway (west) and Gunnery Road (east). First CFI in Florida. Opened July 9, 2019. #

Charlotte, North Carolina Charlotte ( ) is the List of municipalities in North Carolina, most populous city in the U.S. state of North Carolina. Located in the Piedmont (United States), Piedmont region, it is the county seat of Mecklenburg County, North Carolina, Meckl ...

, two-leg CFI, left turns from NC 16 to Mount Holly-Huntersville Road. First CFI in North Carolina. Opened October 18, 2019. #

Olathe, Kansas Olathe ( ) is the county seat of Johnson County, Kansas, United States. It is the List_of_cities_in_Kansas#Highest_population_listing, fourth-most populous city in both the Kansas City metropolitan area and the state of Kansas, with a 2020 Unit ...

, two-leg CFI, left turns from Old 56 Highway to Lone Elm Road. First CFI in Kansas. Opened June, 2021.

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 A traffic island is a solid or painted object in a road that channels traffic. It can also be a narrow strip of island between roads that intersect at an acute angle. If the island uses road markings only, without raised curbs or other physic ...

. 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 could be reduced through the provision of an adequate acceleration lane and merge area. The

Accokeek, MD Accokeek (), "at the edge of the hill" in Algonquin, is a census-designated place (CDP) located in Prince George's County, Maryland, United States. The CDP is located on the Potomac River, borders Charles County and is approximately 17 miles fr ...

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 Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

by 19 tons (17

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

s) per year. 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.

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 New Jersey is a U.S. state, state in the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. It is bordered on the north and east by the state of New York (state), New York; on the ea ...

at the junction of New Jersey Route 168 and US Highway 130, between Haddon Township and

Camden Camden may refer to: People * Camden (surname), a surname of English origin * Camden Joy (born 1964), American writer * Camden Toy (born 1957), American actor Places Australia * Camden, New South Wales * Camden, Rosehill, a heritage res ...

().

References

External links

Federal Highway Administration The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program ...

Alternative Intersection Treatments - CFI
*

University of Maryland The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public university, public Land-grant university, land-grant research university in College Park, Maryland. Founded in 1856, UMD is the Flagship un ...

ATTAP
- Animation of a CFI (QuickTime required). Additional information may be accessed via the links on the left side. *: ''Note that due to the relatively recent installation of the CFI in Baton Rouge, West Valley, UT, and Fenton, MO, some images may not show the existing conditions.''

KSL News story about CFI

CFI open in Natchez, MS
* Seonyeong Cheong, Saed Rahwanji and Gang-Len Chang
Comparison of Three Unconventional Arterial Intersection Designs: CFI, PFI and Upstream Signalized Crossover
ATTAP, University of Maryland, 3 June 2008
''DISPLACED LEFT TURN INTERSECTION Informational Guide''
Federal Highway Administration, Publication No. FHWA-SA-14-068, August 2014 {{DEFAULTSORT:Continuous-Flow Intersection Road junction types Articles containing video clips