A three-level diamond interchange is a type of highway interchange where through traffic on both main roads is grade-separated from intersections which handle transferring traffic.It is similar in design to a three-level stacked roundabout except for its use of (usually signalled) conventional intersections, and can be thought of as two diamond interchanges fused together.
In the field of road transport, an interchange is a road junction that uses grade separation, and typically one or more ramps, to permit traffic on at least one highway to pass through the junction without interruption from other crossing traffic streams. It differs from a standard intersection, where roads cross at grade. Interchanges are almost always used when at least one road is a controlled-access highway or a limited-access divided highway (expressway), though they are sometimes used at junctions between surface streets.
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 transit routes when they cross each other. The composition of such transport axes does not have to be uniform; it can consist of a mixture of roads, footpaths, railways, canals, or airport runways. Bridges, tunnels, or a combination of both can be built at a junction to achieve the needed grade separation.
An intersection is an at-grade junction where two or more roads or streets meet or cross. Intersections may be classified by number of road segments, traffic controls, and/or lane design.
Road enthusiasts sometimes use the terms volleyball interchange or split-level diamond interchange to refer to these interchanges.
A roadgeek is an individual involved in "roadgeeking" or "road enthusiasm"—an interest in roads, and especially going on road trips, as a hobby. A person with such an interest is also referred to as a road enthusiast, road buff, roadfan or Roads Scholar, the latter being a play on the term Rhodes Scholar.
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 the split diamond interchange.
Its at-grade variant is the town center intersection (TCI).
|Location||First Route||Second Route||Notes|
|Cedar Rapids, Iowa, United States||Collector/distributor roads intersect.|
|Detroit, Michigan, United States||I-75 uses frontage roads|
|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, Michigan, United States||I-96 uses frontage roads|
|Jefferson City, Missouri, United States||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 exit 7|
|High Point, North Carolina, United States||I-74 exit 71B|
|Oklahoma City, Oklahoma, United States||A flyover ramp has been added to allow westbound Kilpatrick Turnpike traffic to join State Highway 74 south, bypassing one intersection.|
|Marple Township, Delaware County, Pennsylvania, United States||I-476 exit 5|
|Robinson Township, Washington County, Pennsylvania, United States||PA 576 exit 6; partially completed, temporary terminus of PA 576|
|Frisco, Texas, United States||Includes frontage roads at-grade with interchange|
|Richardson, Texas, United States||Spring Valley Road||Includes frontage roads at-grade with interchange|
|Round Rock, Texas, United States||Includes frontage roads at-grade with interchange|
|Sherman, Texas, United States||Includes frontage roads at-grade with interchange|
|Waco, Texas, United States||Includes frontage roads at-grade with interchange|
|Alexandria, Virginia, United States||Seminary Road||I-395 exit 4|
|Fairfax County, Virginia, United States||The south end of West Ox Road also meets this interchange.|
|Welch, West Virginia, United States||As of 2011, grading has been completed for interchange but interchange itself has not been constructed.|
|Wheeling, West Virginia, United States||Entire interchange is elevated above city streets.|
|Wauwatosa, Wisconsin, United States||An access road for the adjacent Harley-Davidson plant is also part of the interchange.|
|Belmont, Queensland, Australia||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||At; rare design in Germany|
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.
A frontage 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 driveways, shops, houses, industries or farms. Where parallel high-speed roads are provided as part of a major highway, these are also known as local-express lanes.
A stack interchange, or colloquially butterfly junction, is a particular, free-flowing type of design for interchanges, meaning grade-separated road junctions. It is referred to as a directional interchange in the American Association of State Highway and Transportation Officials Policy on Geometric Design of Highways and Streets.
The High Five Interchange is one of the first five-level stack interchanges built in Dallas, Texas. Located at the junction of the Lyndon B. Johnson Freeway and the Central Expressway, it replaces an antiquated partial cloverleaf interchange constructed in the 1960s.
An overpass is a bridge, road, railway or similar structure that crosses over another road or railway. An overpass and underpass together form a grade separation. Stack interchanges are made up of many overpasses.
A cloverleaf interchange is a two-level interchange in which left turns are handled by ramp roads. To go left, vehicles first continue as one road passes over or under the other, then exit right onto a one-way three-fourths loop ramp (270°) and merge onto the intersecting road. The objective of a cloverleaf is to allow two highways to cross without the need for any traffic to be stopped by red lights, even for left and right turns. The limiting factor in the capacity of a cloverleaf interchange is traffic weaving.
A diamond interchange is a common type of road junction, used where a freeway crosses a minor road.
A single-point urban interchange, also called a single-point interchange (SPI) or single-point diamond interchange (SPDI), is a type of highway interchange. The design was created in order to help move large volumes of traffic through limited amounts of space safely and efficiently.
A partial cloverleaf interchange or parclo is a modification of a cloverleaf interchange.
Interstate 380 (I-380) is a 73-mile (117 km) auxiliary Interstate Highway in eastern Iowa. The route extends from Interstate 80 near Coralville to Waterloo. I-380 connects the cities of Cedar Rapids and Waterloo, the state's second- and sixth-largest cities, respectively, to the Interstate Highway System. Except for its last 1 1⁄2 miles (2.4 km) north of U.S. Route 20 (US 20), I-380 runs concurrently with Iowa Highway 27 (Iowa 27), which represents Iowa's portion of the 560-mile (900 km) Avenue of the Saints highway connecting St. Louis, Missouri, with St. Paul, Minnesota.
A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a type of diamond interchange in which the two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway. It is unusual in that it requires traffic on the freeway overpass to briefly drive on the opposite side of the road from what is customary for the jurisdiction. The crossover "X" sections can either be traffic-light intersections or one-side overpasses to travel above the opposite lanes without stopping, to allow nonstop traffic flow when relatively sparse traffic.
In the field of road transport, a turnaround is a type of junction that allows traffic traveling in one direction on a road to efficiently make a U-turn typically without backing up or making dangerous maneuvers in the middle of the traffic stream. While many junction types permit U-turns, the term turnaround often applies to road junctions built specifically for this purpose.
The Ngauranga Interchange is a major interchange in the suburb of Ngauranga, in Wellington City, New Zealand. The Ngauranga interchange connects State Highways 1 and 2 with each other and also to Hutt Road for access to the interisland ferry terminals and alternative access to Wellington City. The majority of traffic in and out of Wellington City uses this interchange.
Interstate 90 Business may refer to several business routes of the Interstate Highway System that connects Interstate 90 with the central business district of various cities bypassed by I-90. Each business route can be either a business loop or a business spur, depending on whether both ends connect to I-90. The business route in each community is considered a unique route. In many cases, these routes are a former section of a U.S. Route.
Interstate 74 (I-74) is the central freeway through the Iowa Quad Cities. It roughly divides Davenport to the west and Bettendorf to the east. The Interstate Highway begins at an interchange with Interstate 80 (I-80) at the northeastern edge of Davenport and continues into Illinois at the Mississippi River by crossing the I-74 Bridge. The freeway was built in stages during the late 1960s and early 1970s.
A wide variety of road signs is displayed in the People's Republic of China. China's traffic signs also closely followed those used in the UK and Japan, China's traffic signs used Highway Gothic font just like the US.
Interstate business routes are roads connecting a central or commercial district of a city or town with an Interstate bypass. These roads typically follow along local streets often along a former U.S. route or state highway that had been replaced by an Interstate. Interstate business route reassurance markers are signed as either loops or spurs using a green shield shaped and numbered like the shield of the parent Interstate highway.
Road signs in Indonesia are standardised road signs similar to those used in other nations but with certain distinctions. As a former Dutch colony, until the 1970s road signs in Indonesia closely followed The Netherlands rules on road signs. Nowadays Indonesian road sign design are a mix of Dutch, German, The American MUTCD, New Zealand, and Japanese road sign features. According to the 2014 Minister of Transportation's Regulation No. 13 concerning Traffic Signs, the official typeface for road signs in Indonesia is Clearview. Indonesia formerly used FHWA Series fonts as the designated typeface though the rules are not being implemented properly.
The Bowers Hill interchange is a large interchange complex where the Hampton Roads Beltway intersects with Interstate 264 (I-264) as well as Military Highway, which carries the three U.S. Highways. It is named for the unincorporated community surrounding it, Bowers Hill, Virginia, which itself is a part of the independent city of Chesapeake.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
Dozens of business routes of Interstate 84 (I-84) exist. The existing and former business routes are located along the western and eastern segments of I-84.