Road enthusiasts sometimes use the terms volleyball interchange or split-level diamond interchange to refer to these interchanges.[2]
Description
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.
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]
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
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.
Includes frontage 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.
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]
Includes frontage roads at-grade with interchange (signed as SH 99 and F.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.
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.
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.
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
Many examples of this interchange type can also be found in Texas; however, the interchanges almost always include the frontage roads as well. If the traffic amounts increase, the interchange is usually converted into a stack interchange, also as the second level of the High Five Interchange.
