Innovative Intersections and Interchanges

← Innovative Intersections main page

Thru-cut icon
Innovative Intersection: Thru-cut
Park and Locust Streets in Vienna, Va.
Innovative Intersections and Interchanges Watch the Innovative Intersections Videos

What Is A Thru-cut?

  • Intersection design where side street through movements are prohibited
  • Side street motorists turn left or right and make another turn at an existing opening to cross the major street
  • Side street left and right turn lanes may be channelized using physical barriers or pavement markings
  • Main intersection may be controlled with a traffic signal, stop signs or yield signs

When Should It Be Considered?

  • On median-divided highways
  • At intersections with low side street through traffic volumes
  • At intersections with heavy major street through and/or left-turn traffic volumes
  • At intersections where side street through movements can be accommodated by rerouting to existing intersections or median openings
  • At intersections with four legs

Benefits

  • Improved safety: Reduces the number of points where vehicles cross paths
  • Increased efficiency: Eliminates the side street through movements, allowing for fewer or shorter traffic signal phases, which reduces delay and increases capacity
  • Shorter wait times: Fewer traffic signal phases means less time stopped at the intersection
  • Cost effective: A thru-cut may be more cost-effective than adding lanes to improve capacity

How to Navigate

Below shows how to navigate a thru-cut intersection.

Conflict Points

The number of conflict points (where travel paths intersect) can be used to evaluate the safety of an innovative intersection or interchange.

There are three categories: crossing, merging or diverging.

In general, merging and diverging conflict points — where vehicles are moving in the same direction — are associated with less severe crash types than crossing conflict points where vehicles are moving in opposite directions.

The diagrams below compare possible vehicle movements and associated conflict points at a conventional four-leg intersection to a thru-cut.

These represent a general case, with one travel lane in each direction, and don't take into account pedestrian or bicycle movements at an intersection or interchange.

When compared to a conventional four-leg intersection, a thru-cut has 8 fewer crossing, 2 fewer merging, and 2 fewer diverging conflict points.

Conventional Intersection: Conflict Points

Conventional Intersection conflict diagram.

Legend

Diagram Legend. Filled circle is diverging, half-filled is merging, empty is crossing.
Conflict Type Count
Crossing 16
Merging 8
Diverging 8
Total:

32 Conflicts

Thru-cut: Conflict Points

Thru-cut conflict diagram.

Legend

Diagram Legend. Filled circle is diverging, half-filled is merging, empty is crossing.
Conflict Type Count
Crossing
Merging
Diverging
Total:

20 Conflicts

Resources

Virginia Department of Transportation

Page last modified: March 18, 2021