First Of Its Kind System In Arizona To Change How Drivers Travel On I-17

New animated video shows how I-17 flex lanes will operate

Motorists driving Interstate 17 north of Phoenix over the last year have seen crews moving dirt and blasting rock to make way for a wider and safer 23-mile stretch of highway between Anthem Way and Sunset Point, as part of the I-17 Improvement Project. When the project is completed in 2025, drivers traveling the approximately 8 miles between Black Canyon City and Sunset Point will experience the first flex lanes on Arizona’s state highway system. 

Today the Arizona Department of Transportation unveiled an animated video created to help explain how the new flex lanes will work. The video can be found on a newly launched webpage dedicated to explaining the system, along with providing information and resources for drivers.


“The flex lanes are an innovative solution that increases safety and helps address congestion in a very challenging geographic area,” said Annette Riley, ADOT’s project manager for the I-17 Improvement Project.

The two-lane flex lane system is being constructed adjacent to the existing southbound lanes and will carry one direction of traffic at a time. The flex lanes are a proven system that safely addresses traffic congestion during peak travel times, or if an unplanned incident creates delays. Typically, the flex lanes will be open to northbound traffic Monday through Saturday, and open to southbound traffic on Sunday. However, the flex lanes will be open, as needed, to whichever direction has the heaviest traffic. They will be operational at all times seven days a week.

The new animated video shows how vehicles will use new crossover lanes to safely access the flex lanes, which will be separated from the existing southbound lanes by a concrete barrier. Steel gates will be installed in the concrete barrier in four locations, allowing emergency responders to clear traffic out of the flex lanes and into the general purpose lanes in the event of an incident.

ADOT’s Traffic Operations Center will manage and monitor the flex lanes remotely using cameras that will be placed throughout the corridor.

  • Dynamic overhead guide signs will alert drivers to the open direction of the flex lanes.
  • Safety systems will be in place to prevent vehicles from entering the flex lanes when traffic is flowing in the opposite direction.
  • A specialized automated net barrier and swing gate system will operate at both ends of the flex lanes.
  • When one direction of the flex lanes is closed, a series of swing gates will be extended. These gates get progressively wider and block access to the flex lanes.
  • Beyond the swing gates, a vehicle-arresting barrier with a net in the down position will also prevent vehicles from entering the flex lanes in the wrong direction.
  • These components of the flex lanes safety system are designed specifically for reversible lane operations in controlling the direction of traffic.

For more information on the entire 23-mile I-17 Improvement Project between Anthem Way and Sunset Point, go to improvingI17.com.