Offset T-intersection

Last updated
Offset T-Intersection Offset T-Intersection (grn).svg
Offset T-Intersection

An offset T-intersection [1] is an at-grade road intersection where a conventional four leg intersection is split into two three-leg T-intersections to reduce the number of conflicts and improve traffic flow. [2] Building the offset T-intersections as continuous green T-intersections (also called seagull intersection), there is a single stop on the arterial road, only. [3] A higher volume of through traffic on the cross road, [4] or on unsignalized intersections, a rebuild to a conventional four-leg intersection may be adequate, also when the offset is a few feet only like staggered junctions causing slower traffic for a longer time on the arterial road. [5]

Seen as a spur route or access road, offset T-intersections can be seen as an A2 or B2 type partial cloverleaf interchange with no arterial road. [6]

See also

Related Research Articles

Roundabout Traffic intersection

A roundabout is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.

U.S. Route 224 (US 224) is a spur of US 24 that runs through the states of Indiana, Ohio and Pennsylvania. It currently runs for 289 miles (465 km) from Huntington, Indiana, at US 24 to New Castle, Pennsylvania, at US 422 Business and Pennsylvania Route 18 (PA 18). It goes through the cities of Canfield, Ohio, Akron, Ohio, and Findlay, Ohio. In Northeast Ohio, US 224 is located a short distance north of the Western Reserve's southern boundary.

California State Route 144 Highway in California

State Route 144 is a state highway in the U.S. state of California that runs through the Sycamore Canyon in Santa Barbara. It travels along Sycamore Canyon Road from its intersection with Alameda Padre Serra at the Five Points Roundabout to Stanwood Drive.

Diamond interchange

A diamond interchange is a common type of road junction, used where a controlled-access highway crosses a minor road.

Single-point urban interchange Highway interchange design

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.

Federal Highway Administration US government agency

The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program and the Federal Lands Highway Program. Its role had previously been performed by the Office of Road Inquiry, Office of Public Roads and the Bureau of Public Roads.

Superstreet Type of high capacity intersection

A superstreet, also known as a restricted crossing U-turn (RCUT), J-turn, or reduced conflict intersection (RCI), is a type of road intersection that is a variation of the Michigan left. In this configuration, in contrast to the Michigan left, traffic on the minor road is not permitted to proceed straight across the major road or highway. Drivers on the minor road wishing to turn left or go straight must turn right onto the major road, then, a short distance away, queue (wait) into a designated U-turn lane in the median. When traffic clears, they complete the U-turn and then either go straight or make a right turn when they intersect the other half of the minor road.

Diverging diamond interchange Freeway interchange design

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.

Continuous-flow intersection Type of large road intersection

A continuous flow intersection (CFI), also called a crossover displaced left-turn, is an alternative design for an at-grade road junction. Vehicles attempting to turn across the opposing direction of traffic cross before they enter the intersection. No left turn signal in the intersection is then necessary. Instead, vehicles traveling in both directions can proceed, including through vehicles and those turning right or left, when a generic traffic signal/stop sign permits.

A junction is where two or more roads meet.

U.S. Route 30 (US 30) is a road in the United States Numbered Highway System that runs from Astoria, Oregon, to Atlantic City, New Jersey. In Indiana, the route runs from the Illinois state line at Dyer to the Ohio state line east of Fort Wayne and New Haven. The 155.96 miles (250.99 km) of US 30 that lie within Indiana serve as a major conduit. The entire length of U.S. Route 30 in Indiana is included in the National Highway System (NHS). The highway includes four-lane, rural sections, an urbanized, four-lane divided expressway, and several high-traffic, six-lane freeway areas. First designated as a US Highway in 1926, US 30 replaced the original State Road 2 (SR 2) and SR 44 designation of the highway which dated back to the formation of the Indiana State Road system. A section of the highway originally served as part of the Lincoln Highway. Realignment and construction projects have expanded the highway to four lanes across the state, and the road is now part of a long stretch of US 30 from New Lenox, Illinois, to Canton, Ohio, where the road has at least four lanes. There are over 40 traffic signals between I-65 at Merrillville and I-69 at Fort Wayne.

Quadrant roadway intersection

A quadrant roadway intersection adds an additional "quadrant roadway" between two legs of an intersection. This roadway adds two three-way intersections in addition to the original four-way intersection moving all left turns or right turns from the main intersection. The design is intended to improve traffic flow by reducing signal timing phases from four to two in the main intersection. The design is intended for intersections where large artery routes meet in an area of dense development and high pedestrian volume.

Indiana State Road 63

State Road 63 (SR 63) in the U.S. state of Indiana is a north–south route in the western portion of the state. Until mid-2008, it covered a distance of just over 96 miles (154 km), but now is a discontinuous route. For 63 miles (101 km), from the city of Terre Haute until it rejoins U.S. Route 41 (US 41) near Carbondale, it is a four-lane divided highway and replaces US 41 as the major north–south artery in this portion of the state.

Interstate 69 in Indiana Highway in Indiana

Interstate 69 (I-69) currently has two discontinuous segments of freeway in the U.S. state of Indiana. The original 157.3-mile-long (253.1 km) highway, completed in November 1971, runs northeasterly from the state capital of Indianapolis, to the city of Fort Wayne, and then proceeds north to the state of Michigan. This original section is also known as Segment of Independent Utility (SIU) 1 in the national plan for expansion of I-69.

State Route 103 (SR-103) is a 0.225-mile-long (362 m) urban minor arterial state highway in the U.S. state of Utah. It branches off from SR-126 in downtown Clearfield and extends east to Interstate 15 (I-15), with the roadway continuing to the Falcon Hill National Aerospace Research Park, just outside Hill Air Force Base. The entire route is located in Davis County and was formed in 1965 coinciding with the construction of I-15.

U.S. Route 136 in Indiana

U.S. Route 136 (US 136) is a part of the United States Numbered Highway that runs from Edison, Nebraska to Speedway, Indiana. In Indiana, it is part of the Indiana State Road system that enters between Danville, Illinois, and Foster, Indiana. The 75.30 miles (121.2 km) of US 136 that lie within Indiana serve as a major conduit. Some sections of the highway is listed on the National Highway System. Various sections are rural two-lane highway and urbanized four-lane divided highways. The easternmost community along the highway is Speedway, near Indianapolis.

U.S. Route 231 in Indiana Highway in Indiana

U.S. Route 231 in Indiana is a main north–south highway in the western part of the state. The southern terminus of US 231 is at the Kentucky state line and the northern terminus is at US 41 just south of St. John. The highway is a mixture of expressway and two-lane roadway. The expressway is mainly in southern Indiana and around the Lafayette area, with the rest mainly being two-lanes.

TRANSYT-7F is a traffic simulation and signal timing optimization program. The primary application of TRANSYT-7F is signal timing design and optimization. TRANSYT-7F features genetic algorithm optimization of cycle length, phasing sequence, splits, and offsets. TRANSYT-7F combines a detailed optimization process with a detailed macroscopic simulation model.

Sidra Intersection is a software package used for intersection (junction) and network capacity, level of service and performance analysis, and signalised intersection and network timing calculations by traffic design, operations and planning professionals.

Split intersection Type of road intersection

A split intersection is a rarely built at-grade variant of the diamond interchange. Compared to a conventional four-leg intersection or road crossing, the arterial road is split into separate carriageways by 200 to 300 feet, allowing a queue of left turning vehicles behind a completed turn into the crossroad without any conflict to oncoming traffic. On the crossroad, the four leg intersection is being replaced by two intersections. The beginning one-way traffic at the fourth leg makes the intersections reduce the number of conflicts similar to a three leg T-intersection to improve traffic flow.

References

  1. Federal Highway Administration (April 2010). "Chapter 6.3.4". Alternative Intersections/Interchanges: Informational Report (AIIR). Federal Highway Administration. FHWA-HRT-09-060. Retrieved 8 May 2016.
  2. Indiana Department of Transportation (14 January 2014). Intersection Decision Guide (PDF). Indiana Department of Transportation. p. 43. Retrieved 8 May 2016.
  3. Transportation Research Board (2010). National Cooperative Highway Research Program (NCHRP) Report 650: Median Intersection Design for Rural High-Speed Divided Highways (PDF). Transportation Research Board. pp. 92–99. doc. P. 84–91.
  4. Federal Highway Administration (July 2008). Intersection Safety Strategies Brochure (PDF). Federal Highway Administration. FHWA-SA-08-008. Retrieved 8 May 2016.
  5. Institute of Transportation Engineers. Convert Two Offset T-Intersections to a Single Four-Legged Intersection (PDF). Institute of Transportation Engineers. Archived from the original (PDF) on 10 May 2016. Retrieved 8 May 2016.
  6. Institut für Straßen- und Eisenbahnwesen am KIT. Entwurf und Bau von Straßen – Teil: Straßenentwurf (PDF) (in German). Institut für Straßen- und Eisenbahnwesen am KIT. pp. SE–5–18 –20. Retrieved 7 September 2013.