The Addison Airport Toll Tunnel, also known as the Addison Airport Tunnel and the Addison Toll Tunnel, is part of the North Texas Tollway Authority (NTTA) system and extends Keller Springs Road under the Addison Airport property. Built for the NTTA, this toll tunnel enables vehicular traffic to travel under rather than around the airport, which expands traffic capacity and eases the notorious congestion of north Dallas and Addison by providing an east–west route between the Dallas North Tollway and Interstate 35E under the Addison Airport runway. It provides motorists a through passage on Keller Springs Road, which once ended on either side of Addison Airport, as an alternate route to the heavily traveled Belt Line Road and Trinity Mills Road. The lanes of the Addison Airport Toll Tunnel toll plaza are equipped for electronic toll collection via TollTag. , the toll charged on the Addison Airport Toll Tunnel is for a two-axle vehicle with TollTag. History In September 1997, tunnelling crews started constructing a two-lane vehicular toll tunnel under Addison Airport. Completed in 1999, the tunnel is approximately in length with a total roadway length of . The NTTA-commissioned project cost nearly $20 million. References External links Addison Airport Toll Tunnel North Texas Tollway Authority Buildings and structures in Dallas County, Texas Tunnels in Dallas Non-freeway toll roads Toll tunnels in the United States Transportation in Dallas County, Texas Tunnels completed in 1999 Road tunnels in the United States Addison, Texas 1999 establishments in Texas