Interstate 26 Boones Creek Road Interchange

Washington County


The project along Interstate 26 at the State Route 354 (Boones Creek Road) interchange (Exit 17) in Washington County involves modification and reconstruction of existing ramps and connector roads. The modifications will transform the exit into a diverging diamond interchange (DDI). The unique crisscross design allows two directions of traffic to temporarily cross to opposite sides of the roadway in order to travel across the overpass, and then cross back and resume the original travel pattern. The DDI uses concrete dividers, stop bars, traffic signals, and extensive signage to guide motorists through the interchange.

Purpose and Need

The existing I-26 / Boones Creek Road interchange was built in the 1960s. The interchange is currently a diamond interchange design, providing access to Boones Creek Road, which is a three-lane roadway with one lane in each direction and a center turn lane.

This area is located in northeast Johnson City in east Tennessee. The planned interchange modifications will not only improve the safety and operation of the Boones Creek Road interchange, but will also alleviate and congestion and support economic growth by providing accessibility to the many current and future commercial, retail, and residential developments.


The I-26 / Boones Creek Road interchange will be modified to a diverging diamond interchange (DDI) design.

The section of Boones Creek Road under I-26, between Browns Mill Boulevard and Lake Park Drive, will be realigned to form the DDI configuration, while existing ramps will be reconstructed and extended, allowing access to and from either direction of I-26 via Boones Creek Road.

The interchange will provide two lanes in each direction on Boones Creek Road. Exit ramps will diverge from the through lanes, while entry ramps will merge with the through lanes. Two signalized intersections will be installed at either end of the widened overpass to control through-traffic movements.

The section of Boones Creek Road between Lake Park Drive and Christian Church Road will be widened to two lanes in each direction with a dedicated center turn lane.

Access to Lake Park Drive will also be adjusted to accommodate the new interchange design.

Pedestrian and bicycle traffic will be accommodated on a shared-use path with crosswalks at the two signalized intersections of the interchange. Sidewalks and bike lanes will resume on both side of Boones Creek Road between Lake Park Drive and Christian Church Road.

The above video is a traffic flow simulation for the Diverging Diamond Interchange planned for I-26 at Boones Creek Road.