Athree-level diamond interchange is a type of highwayinterchange where through traffic on both main roads isgrade-separated from intersections which handle transferring traffic.[1] It is similar in design to athree-level stacked roundabout except for its use of (usually signalled)conventional intersections, and can be thought of as twodiamond interchanges fused together.
Road enthusiasts sometimes use the termsvolleyball interchange orsplit-level diamond interchange to refer to these interchanges.[2]
In a three-level diamond interchange, the two main roads are on separate levels, and on a third level, usually in the middle, there is a square of one-way roads. The square circulates clockwise where traffic drives on the left, or anticlockwise where it drives on the right. At each corner of the square is the terminal of an exit ramp from one main road and an entrance ramp to the other main road.
Traffic transferring from one road to the other to make an overall right turn only passes through one corner of the square, at which point a right turn is made. Transfer traffic making an overall left turn must proceed straight through the first intersection it encounters, turn left at the next, and then proceed straight through a third intersection to enter the other main roadway.
Its two-level variant is thesplit diamond interchange.
Its at-grade variant is thetown center intersection (TCI).
| Location | First Route | Second Route | Notes |
|---|---|---|---|
| Phoenix, Arizona, United States | Indian School Road |  I-17 (Black Canyon Freeway) | Proposed three-level diamond interchange, will include I-17's frontage roads andTexas U-turns for Indian School Road traffic.[3] |
| Tucson, Arizona, United States | Kolb Road |  I-10 (Tucson-Benson Highway) | Proposed combination of a three-level andDiverging diamond interchange, entrances and exits will utilize the diverging diamond element.[4] |
| Doral, Florida, United States | MIA Cargo Viaduct |  SR 826 (Palmetto Expressway) | Northwest 25th Street serves as a frontage road for the MIA Cargo Viaduct. A flyover ramp was added to allow westbound MIA Cargo Viaduct traffic to join SR 826 north.[5] |
| Cedar Rapids, Iowa, United States |  I-380 |  Iowa 100 | Collector/distributor roads intersect. |
| Detroit, Michigan, United States |  I-75 (Walter P. Chrysler Freeway) |  M-102 (8 Mile Road) | I-75 uses frontage roads |
 M-1 (Woodward Avenue) | M-102 (8 Mile Road) | ||
 M-10 (John C. Lodge Freeway) | M-102 (8 Mile Road) | Includes slip ramps from northbound M-10 to westbound M-102, eastbound M-102 to southbound M-10, and westbound M-102 to northbound M-10. M-10 uses frontage roads | |
| Redford Township, Wayne County, Michigan, United States |  I-96 (Jeffries Freeway) |  US 24 (Telegraph Road) | I-96 uses frontage roads |
| Jefferson City, Missouri, United States |   US 50 /US 63 northbound |  US 54 /US 63 southbound | A flyover ramp has been added to allow westbound US 54 traffic to join US 50 east, bypassing one intersection. This addition necessitates the use of a nearby city street to transfer from westbound US 50 to westbound US 54. |
| Asheville, North Carolina, United States |  I-240 |  US 70 | I-240 exit 7 |
| High Point, North Carolina, United States |  I-74 |  US 29 | I-74 exit 71B |
| Oklahoma City, Oklahoma, United States |  SH-74 |    I-344 Toll /Kilpatrick Turnpike | Includesfrontage roads at-grade with interchange (signed as Portland Avenue and West Memorial Road, respectively, for the first and second routes). Two flyover ramps, one from westbound Kilpatrick Turnpike (I-344) to southbound OK-74 and the other from northbound OK-74 to eastbound Kilpatrick Turnpike, are included with the interchange. |
| Marple Township, Delaware County, Pennsylvania, United States |  I-476 |  US 1 | I-476 exit 5 |
| Robinson Township, Washington County, Pennsylvania, United States |  PA Turnpike 576 |  US 22 | PA 576 exit 6 |
| Austin, Texas, United States |  US 183 |  Loop 275 | Includes frontage roads at-grade with interchange |
| Big Spring, Texas, United States |  US 87 |  I-20 | Includes frontage roads at-grade with interchange |
| Conroe, Texas, United States |  SH 242 |  I-45 | Proposed three-level diamond interchange.[6] Currently, at-grade frontage roads and two flyover ramps, one from northbound I-45 to westbound SH 242 (College Park Drive) and the other from westbound SH 242 (Needham Road) to southbound I-45, are included with the interchange. A third flyover from northbound I-45 to eastbound SH 242 is in the planning stages.[7] |
| Dallas, Texas, United States |  Loop 12 (Buckner Boulevard) |   I-30 /US 67 | Includes frontage roads at-grade with interchange |
| Del Valle, Texas, United States |  71 Toll Lanes |  SH 130 Toll (Pickle Parkway) | Includes frontage roads at-grade with interchange. A flyover ramp was added to allow eastbound SH 71 traffic to join SH 130 north. |
| El Paso, Texas, United States | US 54 (Patriot Freeway) |  Loop 375 (Woodrow Bean Transmountain Drive) | Includes frontage roads at-grade with interchange |
| Frisco, Texas, United States |  Sam Rayburn Tollway |  SH 289 (Preston Road) | Includes frontage roads at-grade with interchange (signed asSH 121 for the first route) |
 Dallas North Tollway |  US 380 (University Drive) | Includes frontage roads at-grade with interchange (signed as Dallas Parkway for the first route) | |
| US 380 (University Drive) | SH 289 (Preston Road) | Includes frontage roads at-grade with interchange. | |
| Houston, Texas, United States |   SH 6 /FM 1960 |  US 290 (Northwest Freeway) | Includes frontage roads at-grade with interchange. A flyover ramp was added to allow northbound SH 6 traffic to join U.S. 290 east. |
| SH 6 | I-10 (Katy Freeway) | Includes frontage roads at-grade with interchange. | |
 Beltway 8 (Sam Houston Parkway) |  Hardy Toll Road | Includes frontage roads at-grade with interchange. A flyover ramp was added to allow eastbound Beltway 8 traffic to join Hardy Toll Road north. | |
| FM 1960 (Cypress Creek Parkway) | Hardy Toll Road | Includes frontage roads at-grade with interchange. | |
 Fort Bend Tollway |  Sam Houston Tollway | Includes frontage roads at-grade with interchange (signed as Hillcroft Avenue and Beltway 8, respectively, for the first and second routes). | |
| Fort Bend Parkway Toll Road | SH 6 | Includes frontage roads at-grade with interchange. | |
| Grand Parkway Toll Road | Fort Bend Westpark Tollway | Includes frontage roads at-grade with interchange (signed as SH 99 andF.M. 1093, respectively, for the first and second routes). A flyover ramp was added to allow southbound Grand Parkway traffic to join Westpark Tollway east. | |
| I-45 (North Freeway) | FM 1960 | Includes frontage roads at-grade with interchanges. | |
| I-45 (North Freeway) | Greens Road | ||
| Memorial Drive | Houston Avenue | ||
| Sam Houston Tollway |  US 90 (Crosby Freeway) | Includes frontage roads at-grade with interchanges (signed as Beltway 8 for Sam Houston Tollway). | |
| Sam Houston Tollway |  US 90 Alt. | ||
 SH 249 (Tomball Parkway) | FM 1960 | Includes frontage roads at-grade with interchange. | |
| Lubbock, Texas, United States |   US 62 /US 82 |  Loop 289 | Includes frontage roads at-grade with interchanges. |
 US 84 |  I-27 /US 87 | ||
| Loop 289 | I-27 /US 87 | ||
| Loop 289 |  US 82 /SH 114 | ||
| Mont Belvieu, Texas, United States |  SH 99 Toll (Grand Parkway) | I-10 | Includes frontage roads at-grade with interchange. |
| New Caney, Texas, United States | SH 99 Toll (Grand Parkway) |   I-69 /US 59 | Includes frontage roads at-grade with interchange. Two flyover ramps, one from eastbound SH 99 to northbound I-69/US 59 and the other from northbound I-69/US 59 to westbound SH 99, are included with the interchange. |
| Pasadena, Texas, United States | Sam Houston Tollway |  SH 225 (Pasadena Freeway) | Includes frontage roads at-grade with interchange (signed as Beltway 8 for the first route). |
| Richardson, Texas, United States |  US 75 (Central Expressway) | Spring Valley Road | Includes frontage roads at-grade with interchanges. |
| Round Rock, Texas, United States |  US 79 | SH 130 Toll (Pickle Parkway) | |
| Sherman, Texas, United States | US 75 | US 82 | |
| Spring, Texas, United States | SH 99 Toll (Grand Parkway) | I-45 (North Freeway) | Includes frontage roads at-grade with interchange. Two flyover ramps, one from eastbound SH 99 to northbound I-45 and the other from southbound I-45 to westbound SH 99, are included with the interchange. |
| Sugar Land, Texas, United States | I-69 /US 59 | US 90 Alt. | Includes frontage roads at-grade with interchange |
| Tomball, Texas, United States | SH 99 Toll (Grand Parkway) |  Tomball Tollway | Includes frontage roads at-grade with interchange (signed as SH 249 for the second route). The southern half of the interchange has four flyover ramps: two from northbound Tomball Tollway to east and westbound SH 99 and the other two from SH 99 (west and eastbound) to Tomball Tollway southbound |
| Tyler, Texas, United States |  Loop 49 Toll | I-20 | Includesfrontage roads at-grade with interchanges. |
| Waco, Texas, United States |  SH 6 /Loop 340 | US 84 | |
 I-35 (Jack Kultgen Freeway) |   Bus. US 77 (New Dallas Highway) | ||
| US 84 (Waco Drive) | Bus. US 77 | ||
| Alexandria, Virginia, United States |  I-395 (Shirley Highway) | Seminary Road | I-395 exit 4 |
| Fairfax County, Virginia, United States |  SR 286 (Fairfax County Parkway) | US 29 | The south end of West Ox Road also meets this interchange. |
| Welch, West Virginia, United States |  US 52 (King Coal Highway) |  US 121 (Coalfields Expressway) | As of 2011, grading has been completed for interchange but interchange itself has not been constructed. |
| Wheeling, West Virginia, United States |  I-470 |   US 250 /WV 2 | Entire interchange is elevated above city streets. |
| Wauwatosa, Wisconsin, United States |   I-41 /US 45 |  WIS 190 (Capitol Drive) | An access road for the adjacentHarley-Davidson plant is also part of the interchange. |
| Belmont, Queensland, Australia |  Gateway Motorway (M1) |  Old Cleveland Road (State Route 22) | Two of the ramps are two-way for a short distance to allow access from the interchange to and from local streets. |
| Düsseldorf-Stockum, Germany |  Autobahn 44 |  Bundesstraße 8 | At51°16′16.9″N6°45′1.8″E / 51.271361°N 6.750500°E /51.271361; 6.750500; rare design in Germany |
| Minsk, Belarus | Praspiekt Dziaržynskaha | Praspiekt Žukava | At53°52′59.7″N27°30′19.2″E / 53.883250°N 27.505333°E /53.883250; 27.505333 |
| Mexicali,Baja California, Mexico |  Fed. 5 (Boulevard Adolfo López Mateos) |  Fed. 2 (Boulevard Lázaro Cárdenas) | At32°37′28″N115°27′9″W / 32.62444°N 115.45250°W /32.62444; -115.45250 |
Many examples of this interchange type can also be found in Texas; however, the interchanges almost always include thefrontage roads as well. If the traffic amounts increase, the interchange is usually converted into astack interchange, also as the second level of theHigh Five Interchange.