Inverted SPUI . Ramps are located between
carriageways. A rarely built variant of the SPUI is the
inverted SPUI, in which the
carriageways of the free-flowing road are separated, with left on- and offramps running between the carriageways and coming to a single
at-grade intersection with the cross street. This can be built less expensively than a standard SPUI by allowing for shorter, simpler bridges at the interchange. However, this inverts the usual convention of placing carriageway on- and offramps on the right side of the carriageway, instead placing them on the left side, usually considered the
passing lane.
Notable examples •
Interstate 290 in
Oak Park, Illinois, near
Chicago, at South Harlem Avenue () and at South Austin Boulevard (). •
Greensboro, North Carolina, connecting
West Wendover Avenue to South Holden Road (). •
Interstate 244 in
Tulsa,
Oklahoma, at Sheridan Road () and at Memorial Drive (). •
U.S. Route 422 in
Reading, Pennsylvania, at
U.S. Route 222 Business (). •
State Route 18 in
St. George, Utah, at Red Hills Parkway. •
Woodall Rogers Freeway (TX Spur 366), in
Dallas, Texas at Riverfront Boulevard, immediately before the
Margaret Hunt Hill Bridge (). •
A12 Westlink in
Belfast, Northern Ireland, at
Divis Street Continuous green T (or seagull) hybrid There is also a variant of the inverted SPUI, which can be used when a side road ends at, rather than crossing, a free-flowing road. In this variant, one carriageway of the free-flowing road is grade-separated from the side road, as with a typical inverted SPUI, while the other carriageway of the free-flowing road is at-grade with but still separated from the side road, as found in a
continuous green T- (or seagull) intersection. There is one such interchange in
Pultney Township, Belmont County, Ohio, between
State Route 7 (SR 7) and
Interstate 470 (I-470) at . The ramps leading to and from I-470 run west of, but are not directly connected to, SR 7; these ramps form the "side road" at this interchange. The southbound carriageway of SR 7 bridges over the interchange, while its northbound carriageway remains at-grade. SR 7's left on- and offramps run between its carriageways, meeting the I-470 ramps at an at-grade intersection. The I-470 ramps proceed to a
trumpet interchange with I-470. I-470 itself bridges over both carriageways of SR 7 a short distance north of the I-470/SR 7 ramps' intersection. This design was likely chosen not for cost savings but because the northbound carriageway of SR 7 is bordered by railroad tracks, commercial properties, and the
Ohio River and because I-470 bridges the river just east of SR 7—a more conventional interchange design was likely more difficult to achieve. There is another such interchange in
Millvale, Pennsylvania, near
Pittsburgh, at the junction between
Pennsylvania Route 28 (PA 28) and the
40th Street Bridge. The northbound carriageway of PA 28 passes under the interchange, with lefthand ramps meeting at the bridge (the northbound entrance ramp does not provide direct access to PA 28). The southbound carriageway of PA 28 has a continuous green T-intersection with the bridge. A similar interchange exists in
Coal Grove, Ohio, at the junction of
U.S. Route 52 (US 52) with the
Ben Williamson Memorial Bridge and the
Simeon Willis Memorial Bridge, which cross the
Ohio River and lead to and from
Ashland, Kentucky, respectively. The eastbound carriageway of US 52 passes under the interchange, with lefthand exit and entrance ramps to the bridges. The westbound carriageway of US 52, which narrows to one throughlane, has a continuous green T-intersection with the bridges. The ramps cross each other
at-grade, with a
traffic light-controlled intersection. An interchange, like that in Millvale, Pennsylvania, formerly existed at the junction of SR 7 and
SR 822 at the now-demolished
Fort Steuben Bridge in
Steubenville, Ohio. The northbound carriageway of SR 7 passed under the bridge, with lefthand ramps meeting the bridge approach, while the southbound carriageway had a continuous green T-intersection with the bridge.
Offset SPUI An offset SPUI is similar to a diamond interchange, however, by making two of the ramps
flyovers or flyunders, all ramps are pushed to one side of the highway, where they meet the surface street at a single intersection. An example of this is the interchange between
Interstate 225 and Alameda Avenue near the
Town Center at Aurora shopping center in
Aurora, Colorado, United States (at ). Another example is the interchange between
Minnesota State Highway 36 and Rice Street at the border of
Little Canada and
Roseville, Minnesota.
Three-level SPUI A three-level SPUI is similar to a standard SPUI but includes an additional grade separation allowing for free-flowing through traffic on the crossroad; such through traffic thus bypasses the signalized intersection. The remaining intersection, free of the crossroad's through traffic, uses a
two-phase traffic signal for handling the left turns in pairs, similar to the traffic flow at an inverted SPUI. Examples include: •
Jalan Tun Abdul Razak (Federal Route 1) in
Johor Bahru,
Johor,
Malaysia, at
Jalan Lingkaran Daram (Federal Route 188). Jalan Lingkaran Daram passes over the SPUI. (). •
Central Expressway (CTE) in
Singapore, at
Braddell Underpass. Braddell Road passes under the SPUI. (); • Jinxing Avenue (
Chinese: 金星大道
Pinyin: Jīnxīng dàdào) in
Yubei District,
Chongqing,
China, at Food City Avenue (Chinese: 食品城大道 Pinyin: Shípǐn chéng dàdào). This is a partial three-level SPUI in which one of the ramps from Food City Avenue to Jinxing Avenue passes under the SPUI. (). ==References==