14.5.1 Overview

A Continuous Green-T (CGT) is a T-intersection design where one major street direction of travel (the top side of the “T”) can pass through the intersection without stopping and opposite major street direction of travel is typically controlled by a traffic signal.
Left-turn vehicles from the side street use a channelized receiving lane on the major street to merge onto the major street. A CGT intersection is typically signalized but can also be designed without a traffic signal. Intersections of this type are common and have performed well in other states including Florida, Utah, Nevada, and New York. CGT intersections reduce delay at high-volume locations by removing the need to stop both directions of mainline traffic to accommodate left-turns.
A CGT is also known as:
  • Turbo-T intersection;
  • High-T intersection; and
  • Seagull intersection.
Figure 14-15
shows an example of a GCT intersection.
Example of a CGT Intersection ( click in image to see full-size image)
Figure 14-15: Example of a CGT Intersection
Source: Innovative Intersections – Continuous Green-T (CGT) (VDOT)
Benefits of a CGT include:
  • Improved safety –
     channelization of left-turn vehicles from the side street reduces the potential for angle crashes.
  • Increased efficiency –
     because one direction of travel on the major street is free-flow, more green time can be provided to the other movements, reducing delay at the intersection.
  • Free-flow in one direction –
     one direction of travel on the major street never stops, which improves traffic signal synchronization and reduces corridor travel times.
Conditions where a CGT may not be suitable include:
  • If there is another intersection beyond the CGT that experiences congestion. This may cause spillback into the CGT and prevent the resultant free-flow;
  • Intersections where pedestrians need to cross the major street; and
  • Highly developed areas. The CGT may restrict access to existing driveways on the continuous flow lanes.