Dumbbell in
Clarington, Ontario, Canada. This one features a loop ramp. The ramp intersections may also be configured as a pair of
roundabouts This type of interchange is common in the
United Kingdom and
Ireland, and is becoming increasingly common in the
United States. Examples of dumbbell interchanges in the United States are located on
Interstate 35 in
Medford, Minnesota, and on
Interstate 87 in
Malta, New York. An example in Canada is found on the
Pat Bay Highway in
North Saanich, British Columbia, near
Victoria International Airport. One or both roundabouts in the dumbbell interchange may also contain side lanes to increase the capacity. A good example of such a
"turbo" dumbbell interchange, which was formerly a half cloverleaf, can be seen in
Jülich, Germany at . There are interchanges similar to dumbbells in which the ramps do not meet the roundabouts at intersections; these more closely resemble bowtie intersections. One such interchange exists at the junction between the
Ruta Interbalnearia and Route 35 North near
La Floresta, Uruguay ().
Dogbone in
Columbus, North Carolina, United States A variation of the dumbbell interchange, often called a
dogbone interchange (due to its aerial resemblance to a real or toy
dog bone), and sometimes also called a
double roundabout interchange, more compact examples, which show less of the characteristic "dog bone" shape, are located along
Keystone Parkway in
Carmel, Indiana, United States. Several interchanges similar to those along Keystone Parkway are being built along the new
US 31 freeway under construction in northern Indiana. There are some hybrid interchanges of dumbbell and dogbone having one raindrop and one full roundabout. This is made when the roundabout intersects more roads than the cross street and ramps. Some examples are at exit 38 of the
N7 road in
Groningen, Netherlands (at ); and
Ennis Avenue (
National Route 1) at
Safety Bay Road (
State Route 18 /
Tourist Drive 202) on the border of the suburbs of
Waikiki and
Warnbro in the
City of Rockingham,
Western Australia (at ). A
tennis ball interchange resembles a dogbone interchange, with the difference being that right turning movements (in a country where traffic
drives on the left) cut through the roundabouts like a regular diamond interchange instead of going around the roundabout. Such a design is found in
Perth, Western Australia, between
Roe Highway (
State Route 3) and Berkshire Road (at ).
Tight diamond A
tight diamond interchange (
TDI), also known as a
compressed diamond interchange or a
tight urban diamond interchange (
TUDI), is sometimes used in areas where there is insufficient
right-of-way for a standard diamond interchange. The pair of intersections where the ramps meet the minor road are closely spaced. This spacing forces the turn lanes for each direction to run beside each other, causing the minor road to be wider than it would be if it were a standard diamond.
Caltrans classifies this type as Type L-1.
Single-point urban , demolished in the early 2010s A
single-point urban interchange (
SPUI) is built with a large over- or clear underpass providing space for a single traffic signal controlled intersection with the
ramps and the
cross street. Caltrans classifies this type as Type L-13.
Diverging diamond In a
diverging diamond interchange (
DDI) or (
DCD), the two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway to save the third traffic signal phase.
Three-level diamond In a
three-level diamond interchange, the cross street is built in a third level with free flowing traffic as a second
arterial road. The intersection is split up into four intersections, handling just two conflicting directions each. Its two-level variant is the split diamond interchange. Its at-grade variant is the
town center intersection (TCI).
Continuous-flow diamond A single-leg
continuous-flow intersection (CFI) was built in 2014 in
San Marcos, Texas, at the intersection of Aquarena Springs Drive (
Loop 82),
Interstate 35's southbound
frontage road and I-35's southbound-to-northbound
Texas U-turn. A two-leg CFI, also in San Marcos, was built in 2015 at the intersection of Hopkins Street (
State Highway 80), 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.
Split diamond A
split diamond interchange has its ramps "split" between two crossroads, typically with an exit ramp/entrance ramp pair serving each of the crossroads. The crossroads themselves may be one-way or two-way, and are most often connected by frontage roads, usually one-way.
Other Where
HOV lanes are present for
carpooling, the ramps of a diamond interchange may be folded to the inside lanes instead of the outside. In
urban areas this saves some space as well as requiring only one intersection instead of the two one-way intersections, which in
rural or
suburban areas can be turned into a
single-point urban interchange. This in turn reduces waiting time for motorists at
traffic lights on the smaller road, which may be a large local
thoroughfare with heavy traffic. In
Henrietta, New York, Jefferson Road (
NY-252) crosses West Henrietta Road (
NY-15) on a modified diamond interchange, where traffic merges onto NY-252 at signalized intersections without any merge lanes, as well as
Texas U-turns and
RIROs on the ramps.
Gallery AS Hantel.svg|A dumbbell interchange AS Knochen.svg|A dogbone interchange File:AS TUDI.svg|A tight urban diamond interchange (TUDI) File:AS CFL.svg|A contraflow left turn interchange File:TUDI TX-CFI.svg|Continuous-flow diamond Split diamond interchange.svg|Split diamond interchange ==See also==