Wikipedia

Michigan left

For the Arkells album, seeMichigan Left (album).
This article reflects countries thatdrive on the right.For countries that drive on the left, reverse right and left.

AMichigan leftorP-turnis anat-grade intersectiondesign that replaces each left (farside) turn at an intersection between a (major)divided roadwayand a secondary (minor) roadway with the combination of a right (nearside) turn followed by a U-turn, or a U-turn followed by a right (nearside) turn, depending on the situation. It is in use in numerous countries.

Standard design on a wide median[1]
Stylized depiction of the design inGrand Haven,Michigan, atUS 31and Robbins Road (north to the right), showing the additional area necessary to make a turn on a narrow median[1]43°2′40.18″N86°13′12.57″W/ 43.0444944°N 86.2201583°W/43.0444944; -86.2201583(US 31 at Robbins Road, Grand Haven, Michigan)

Terminology

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This intersection design was given the name "Michigan left" due to its frequent use along roads and highways in the U.S. state ofMichigansince the late 1960s.[2]In other contexts, the intersection is called amedian U‑turn crossoverormedian U‑turn,orrestricted crossing U-turn(RCUT).[1][3][4]The design is also sometimes referred to as aboulevard left,[5]aboulevard turnaround,[6]anindirect left turn,[2][7]aMichigan loon,[8]aJ‑turn,[9]P‑turnor a"ThrU Turn" intersection.[10][11]

Description

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Two versions of signs posted along an intersecting road or street at an intersection.
Top:most commonly used; state of Michigan standard.[12]
Bottom:lesser-used variant.

The design occurs atintersectionswhere at least one road is adivided highwayorboulevard,and left turns onto—and usually from—the divided highway are prohibited. In almost every case, the divided highway is multi-laned in both directions. When on the secondary road, drivers are directed to turn right. Within1⁄4mile (400 m), they queue into a designatedU-turn (or cross-over) lanein themedian.When traffic clears they complete theU-turnand go back through the intersection. Additionally, the U-turn lane is designed for one-way traffic.

Similarly, traffic on the divided highway cannot turn left at an intersection with a cross street. Instead, drivers are instructed to "overshoot" the intersection, go through the U-turn lane, come back to the intersection from the opposite direction, and turn right.

When vehicles enter the cross-over area, unless markings on the ground indicate two turning lanes in the cross-over, drivers form one lane. A cross-over with two lanes is designed at high-volume cross-overs, or when the right lane turns onto an intersecting street. In this case, the right lane is reserved for vehicles completing the design. Most crossovers must be made large enough for semi-trailer trucks to complete the crossover. This large cross-over area often leads to two vehicles incorrectly lining up at a single cross-over.

A Michigan left generally allows through traffic on the minor crossroads to proceed straight across the major road or highway, especially on the more heavily traveled minor roads.

Its design also is promoted as part of the Federal Highway Administration'sEvery Day Counts initiativewhich started in 2011.[13]

Variations

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Narrow median

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When the median of a road is too narrow to allow for a standard Michigan left maneuver, a variation can be used that widens the pavement in the opposite direction of travel. This widened pavement is known as a "bulb out"[10]or a "loon" (from the pavement's aerial resemblance to theaquatic bird).[8]Such a design is sometimes referred to as aMichigan loon;inUtah,as athrU turn,where one passesthroughthe intersection before aU-turn.[10]

Grade separation

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InGuadalajara, Mexico,there is a grade-separated variation of this setup at the intersection of Mariano Otero Avenue and Manuel Gómez Morín Beltway (20°37′50″N103°26′06″W/ 20.630666°N 103.434981°W/20.630666; -103.434981).[14]Traffic flowingthrough Mariano Otero Avenue is routed onto an overpass above the beltway, with two access roads allowing right turns in all four possible directions; the U-turns, meanwhile, are built underneath the beltway and allow the left turn movements from Mariano Otero Avenue to the beltway.

Superstreet

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Main article:Superstreet

A variation of the Michigan left that prohibits through traffic on minor roads from crossing the major road or highway, is most commonly called a superstreet or a "restricted crossing U‑turn" (RCUT).[15]In contrast to the standard Michigan left, left turns from the major road or highway to minor roads are usually allowed, although there is a variation that prohibits such turns.

Examples

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Angola

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The capital city of Angola,Luanda,makes widespread use of a simplified variant of this type of intersection on its two- and three-lane, median-separated throughways instead of using traffic lights. Larger junctions use this intersection type instead of much more costly grade-separated interchanges.

Australia

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In Australia, where traffic drives on the left, theVictorianstate government in 2009 introduced the "P-turn", similar to the Michigan left, at the intersection ofMoorooduc Highway(C777) and Cranbourne-Frankston Road (State Route 4) in the southeasternMelbournesuburb ofFrankston.This requires right-turning vehicles to turn left then make a U-turn. As of May 2015, local residents had called for its removal.[16][17]

On April 16, 2018, a P-turn was introduced at the intersection ofHoddle Street(State Route 29) and Johnston Street (State Route 34) inAbbotsford, Victoria.Another P-turn was added in 2019 at the intersection of thePunt Roadsection of State Route 29 andSwan Street(State Route 20) inRichmond.[18]

Brazil

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The Michigan left is a commonly used design in Brazil especially inSão PauloandParaná.

Canada

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InOttawa,Ontario, a Michigan left exists to proceed fromBank StreettoRiverside Drivein both directions.

The design has been proposed inToronto,Ontario, to relieve motorists who wish to make a left-turn on roadways that will contain a proposed streetcar line by theTransit Cityproject.

A Michigan left exists inWindsor, Ontario,on Huron Church Road, just north of theE.C. Row Expressway,where a narrow-median variant put in place years ago is now seldom used due to the realignment of the expressway in conjunction with the construction of theHerb Gray Parkway.

InSaskatoon,Saskatchewan, a Michigan left pairing exists on8th Street,just west of its interchange withCircle Drive,as well as a few other U-turn lanes as one heads westbound.

Hong Kong

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This is the design at some busy junctions in Hong Kong. In Hong Kong Island examples include the junction ofFleming RoadandHarbour RoadinWan Chai North,and the junction of Hennessey Road andCanal Road FlyoverinWong Nai Chung.InKowloonthis design exists between Cheong Wan Road and Hong Chong Road/Salisbury Road.

Philippines

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A no left-turn scheme at the intersection ofBonny Serrano AvenueandKatipunan Avenue(part ofCircumferential Road 5) inQuezon City,Metro Manila

In thePhilippines,theMetropolitan Manila Development Authority(MMDA) underBayani Fernandoimplemented a "no left-turn" scheme in the early 2000s along several major roads in Metro Manila, prohibiting motor vehicle traffic from turning left at intersections and instead requiring them to make aU-turnat designated U-turn slots and making a right turn after. The scheme was designed to mimic the Michigan left turn design by creating continuous traffic, mitigating bottlenecks caused by traffic light signals.[19]The MMDA claimed that its "no left-turn" scheme in addition to itsNo Contact Apprehension Policyand road obstruction clearing campaign has increased the average travel speed along major thoroughfares from 14.5 km/h (9.0 mph) in July 2001 to 17.37 km/h (10.79 mph) in June 2003.[20]

However, the implementation of the "no left-turn" scheme in Metro Manila was controversial, as it was notorious among motorists for causing longer travel distances due to having to navigate to the nearest U-turn slot and for incidents of motorists missing their U-turn slot due to difficulties navigating to it safely. Several academic studies were also made on the "no left-turn" scheme, summarizing that the scheme induces longer travel time and only works with low car inflow and minimal lane changing maneuvers, with the U-turn slots eventually becoming congested themselves.[19][21]Since then, many of these U-turn slots were closed and left-turning at most intersections was restored, although some still remain along roads such asEDSA,Quezon Avenue,andCircumferential Road 5.

Mexico

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U-turn intersections are very common throughout Mexico, particularly in Mexico City.

United Kingdom

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A similar style P-turn is used in the junction of theA4 Great West Roadand A3002Boston ManorRoad inBrentford,England.

United States

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In 2013, Michigan lefts were installed inAlabamafor the first time, in several locations along heavily traveledU.S. Route 280in metroBirmingham.[22]

Tucson, Arizona,began introducing Michigan lefts in 2013, at Ina/Oracle and on Grant Road. Their reception has been mixed.[23]

Indianapolis, Indiana,introduced the Michigan Left in 2013 at the intersection of 96th Street, and Allisonville Road (near the surrounding cities ofFishers, Indiana). The city has announced plans to tear out the Michigan Left due to its unpopularity amongst the locals[24]

In November 2018, theAda County Highway Districtcompleted work on a ThrU-turn intersection at the State Street/Veterans Memorial Parkway/36th Street intersection inBoise, Idaho.[25]

The design is relatively common inNew Orleans, Louisiana,and its suburbMetairie,where city boulevards may be split bystreetcartracks,[26]and suburban thoroughfares are often split by drainage canals.[27]Some intersections using this design are signed similarly to those in Michigan, but with more descriptive text;[28]however, in some cases the only signage is "No Left Turn" and drivers are left to figure it out for themselves.[29]

Since the redevelopment of the intersection betweenUniversity Boulevard (MD 193)andColesville Road (US 29)inSilver Spring, Maryland,a Michigan left has been used to increase efficiency of traffic through an otherwise underdeveloped and congested intersection. Due to its proximity to theCapital Beltway,heavy traffic is handled more safely and efficiently.[citation needed]

TheMichigan Department of Transportationfirst used the modern design at the intersection of8 Mile Road(M-102) and Livernois Avenue[30](42°26′46″N83°08′28″W/ 42.4461°N 83.141°W/42.4461; -83.141(M-102 (8 Mile Road) at Livernois Avenue))[31]inDetroitin the early 1960s. The increase in traffic flow and reduction in accidents was so dramatic (a 30–60% decrease[32]) that over 700 similar intersections have been deployed throughout the state since then.[33]Michigan keeps building Michigan lefts where the opportunity presents itself, completing a rebuild of a dangerous stretch of highway (US 131inThree Riversin 2021).[34]

North Carolinahas been implementing Michigan lefts alongUS 17in the southeastern part of the state, outsideWilmington.[33]In 2015, a Michigan left was constructed at the intersection of Poplar Tent Road and Derita Road in theCharlottesuburb ofConcord.[citation needed]

Columbus, Ohiointroduced a Michigan left at the intersection ofSR 161and Strawberry Farms Boulevard in 2012.

At least two Michigan lefts have existed inTexas.One was located at the intersection of Fondren Road andBellaire BoulevardinHoustonfrom the 1980s through 2007, when it was replaced with conventional left-turn lanes. Another was built in mid-2010 inPlanoat the intersection of Preston Road and Legacy Drive.[35]In January 2014, the city announced plans to revert the turn to a traditional intersection as a result of drivers' confusion.[citation needed]A section of State Highway 71 east of Austin-Bergstrom International Airport at FM 973 in Austin, Texas did have a signalized Michigan U-turn that was constructed in 2014—this was a temporary fix until the SH71 tollway over SH130 (including the re-routing of FM973) was completed in early 2016.[citation needed]There are multiple Michigan left turns currently being used along US 281 north of Loop 1604 in San Antonio. These were adopted as a short-term solution for traffic issues as development expanded north, but will likely be phased out as US 281 is elevated.[citation needed]

In 2024, Virginia instituted a Michigan turn at the intersection of Fredericksburg Rd. and US 29 in Greene County.

The city ofDraper, Utah,a suburb ofSalt Lake City,announced in 2011 that it would be building Utah's first "ThrU Turn" at the intersection of 12300 South and State Street, just offInterstate 15through Salt Lake County. Construction began in summer 2011 and was completed in fall 2011.[10][36][37]Other similar intersections were implemented inSouth Jordan[38]andLayton.[39]

Applicable traffic studies

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This type of intersection configuration, as with any engineered solution to a traffic problem, carries with it certain advantages and disadvantages and has been subject to several studies.

Studies have shown a major reduction in left-turn collisions and a minor reduction in merging and diverging collisions, due to the shifting of left turns outside the main intersection. In addition, it reduces the number of differenttraffic lightphases, significantly increasing traffic flow. Because separate phases are no longer needed for left turns, this increases green time for through traffic. The effect on turning traffic is mixed. Consequently, the timing of traffic signals along a highway featuring the design is made easier by the elimination of left-turn phases both on that highway and along intersecting roadways contributing to the reduction of travel times and the increased capacity of those roadways.[1]

It has been shown to enhance safety for pedestrians at these intersections, since they only encounter through traffic and vehicles making right turns. The elimination of left turns removes one source of potential vehicle-pedestrian conflict.[1]One minor disadvantage of the Michigan left is the extra distance required for the motorist to drive. Sometimes the distance to the turnaround is as far away as1⁄4mile (400 m) past the intersection. This design leads to each motorist driving an additional1⁄2mile (800 m) to make a left turn. It also results in left-turning vehicles having to stop up to three times in the execution of the turn.

See also

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References

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  1. ^abcdeFederal Highway Administration(August 2004)."Alternative Intersection Treatments".Signalized Intersections: Informational Guide.Federal Highway Administration. Archived fromthe originalon May 10, 2009.RetrievedAugust 1,2011.
  2. ^abMichigan Department of Transportation(July 19, 2010)."Michigan Lefts".Michigan Department of Transportation.RetrievedDecember 20,2010.
  3. ^Federal Highway Administration(August 2014)."Median U-Turn Intersection Informational Guide"(PDF).Archived fromthe original(PDF)on April 23, 2015.
  4. ^North Carolina State University(August 1, 1999)."Unconventional Left-Turn Lanes Reduce Traffic Accidents, Congestion"(Press release). North Carolina State University. Archived fromthe originalon March 25, 2007.RetrievedDecember 20,2010.
  5. ^Indiana Department of Transportation."Traffic Operations: Median U-Turns".Indiana Department of Transportation.RetrievedJune 24,2017.
  6. ^City of Farmington Hills, Michigan(October 18, 2001)."Minutes, Planning Commission Public Hearing, September 20, 2001"(PDF).City of Farmington Hills, Michigan. Archived fromthe original(PDF)on September 27, 2007.RetrievedAugust 1,2011.
  7. ^Hall, Jocelyn (September 18, 2015)."M-20 Traffic Restrictions at Leaton Road Starting Sept. 23"(Press release). Michigan Department of Transportation.RetrievedFebruary 4,2019.Indirect left turns, or Michigan Lefts, near the intersection will be available.
  8. ^abHughes, Warren; Chappell, Debra; Chen, Shyuan-Ren (Clayton) (January 2005)."Geometric Design Treatments".Innovative Intersection Safety Improvement Strategies and Management Practices: A Domestic Scan.Federal Highway Administration. Archived fromthe originalon August 30, 2009.RetrievedAugust 17,2013.
  9. ^Mississippi Department of Transportation (June 23, 2022)."J-Turn Intersections Implemented Across State (Video)"(Press release). Mississippi Department of Transportation.RetrievedJune 23,2022.
  10. ^abcdUtah Department of Transportation."Overview".Thru Turn Intersection.Utah Department of Transportation. Archived fromthe originalon June 23, 2012.RetrievedSeptember 24,2011.
  11. ^Doctor, Mark; Shaw, Jeff; Merritt, George (April 4, 2013)."Intersection and Interchange Geometrics".Every Day Counts 2 Spring Virtual Summits - 21st Century Solutions(PDF). Federal Highway Administration.RetrievedAugust 17,2013.
  12. ^Michigan Department of Transportation, Traffic and Safety division (2012)."Standard Highway Signs: Route Marker Signs".p. 101.Sign M8-5.
  13. ^Schroeder, Bastian; Cunningham, Chris; Ray, Brian; Daleiden, Andy; Jenior, Pete; Knudsen, Julia (August 2014).Diverging Diamond Interchange Informational Guide(PDF).Washington, DC: Federal Highway Administration Office of Safety.
  14. ^"Mariano Otero Avenue and Manuel Gómez Morín Beltway, Guadalajara"(Map).Google Maps.RetrievedDecember 20,2010.
  15. ^Federal Highway Administration(August 2014)."Restricted Crossing U-Turn Intersection Informational Guide"(PDF).p. 10. Archived fromthe original(PDF)on April 24, 2015.
  16. ^Carton, Donna; Morris, Deborah (March 2, 2009)."P-turn to shut Frankston residents out of their street".Frankston Standard Leader.Archived fromthe originalon November 18, 2012.RetrievedDecember 20,2010.
  17. ^Tatman, Christian (May 15, 2015)."Roads Minister Luke Donnellan says Frankston's P-turn will remain".Frankston Standard Leader.RetrievedJanuary 7,2016.
  18. ^"Melbourne gets another P-turn with Swan Street changes".ABC News.March 17, 2019.RetrievedSeptember 11,2020.
  19. ^abVillarete, Nigel (July 17, 2014)."Understanding U-turn slots".The Philippine Star.RetrievedJanuary 8,2023.
  20. ^Clapano, Jose (June 15, 2003)."Jaworski to Bayani: Have a heart".The Philippine Star.RetrievedJanuary 8,2023.
  21. ^Chanco, Boo (August 24, 2007)."The U-turns of Bayani Fernando".The Philippine Star.RetrievedJanuary 8,2023.
  22. ^Smith, Mike (September 5, 2013)."US 280: 'Michigan Left' U-turn at Valleydale Scheduled to Be in Effect for Friday Morning Commute (animation)".The Birmingham News.
  23. ^"Little Love for Michigan Left".Arizona Daily Star.October 14, 2013.RetrievedMarch 3,2014.
  24. ^"Fishers does U-turn on Michigan Left".Indy Star.February 22, 2022.RetrievedMay 15,2023.
  25. ^"State Street/Veterans Memorial Parkway/36th Street Intersection".Ada County Highway District.RetrievedMarch 11,2019.
  26. ^"S Claiborne Ave and S Carrollton Ave, New Orleans"(Map).Google Maps.RetrievedMay 17,2013.
  27. ^"W Metairie Avenue and Cleary Avenue, Metairie"(Map).Google Maps.RetrievedFebruary 1,2013.
  28. ^"W Metairie Avenue near Cleary Avenue, Metairie".Google Street View.February 2022.RetrievedMarch 11,2023.
  29. ^"Northbound on S Carrollton Ave at S Claiborne Ave, New Orleans".Google Street View.January 2021.RetrievedMarch 11,2023.
  30. ^"Revisiting the Origin of the 'Michigan Left'".Michigan Radio. September 15, 2014.RetrievedNovember 26,2017.
  31. ^"8 Mile Road and Livernois Avenue"(Map).Google Maps.
  32. ^Klinefelter, Quinn (October 5, 2015)."CuriosiD: Where Did the Michigan Left Come From?".Detroit:WDET-AM.RetrievedNovember 25,2017.
  33. ^abSweeney, Kate."The Michigan Left Superstreet: Heading Eastbound: A Midwestern traffic pattern takes a detour to North Brunswick County".North Brunswick Magazine.RetrievedNovember 26,2017.
  34. ^Schirripa, Nick (March 17, 2020)."Final Season of US 131 Reconstruction in Three Rivers Starts Monday"(Press release). Michigan Department of Transportation.RetrievedOctober 21,2021.
  35. ^Kim, Theodore (March 23, 2010)."Officials Worry that 'Michigan Left Turn' at Plano Intersection Will Confuse Drivers".Dallas Morning News.RetrievedDecember 20,2010.
  36. ^Davidson, Lee (November 11, 2011)."Newfangled Intersection to Open Monday in Draper".The Salt Lake Tribune.RetrievedAugust 17,2013.
  37. ^"U-Turns Replace Left Turns at Draper intersection".KTVX.November 14, 2011.RetrievedAugust 17,2013.
  38. ^"'Thru Turn' in Effect at Bangerter and 7800 South Intersection ".West Jordan Journal.Archived fromthe originalon February 9, 2013.RetrievedJune 11,2012.
  39. ^Utah Department of Transportation."Layton Improved UDOT Open House Presentation".Utah Department of Transportation. Archived fromthe originalon July 1, 2014.RetrievedMarch 3,2014.
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