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Diverging Diamond Interchange

A Diverging Diamond Interchange (DDI) is a new intersection design that addresses congestion by allowing vehicles to travel more quickly through an intersection. A DDI works by creating a diamond-shaped pattern in the roadway that temporarily shifts traffic to the left of the roadway prior to entering the intersection. Two-phase traffic signals are installed at the roadway crossover points. Once on the left side of the roadway, vehicles can freely turn left rather than waiting for oncoming traffic to clear or for a left-turn signal. Through-traffic on the frontage road is handled via a collector-distributor lane, or intersection bypass lane, which bypasses the signalized intersection, allowing drivers to avoid the traffic signal. Benefits include improved:

  • Safety
  • Mobility
  • Connectivity

There is also a DDI at I-35 and RM 1431 in Williamson County.

Watch the DDI explanatory video to see how it works. You can also read the DDI fact sheet to learn more.

Diverging Diamond Interchange (DDI)

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