The Airport Tunnel, also known as the Sepulveda Boulevard Tunnel, is a highway tunnel in Los Angeles, carrying Sepulveda Boulevard underneath the two runways (25L/25R) and taxiways on the south side of the Los Angeles International Airport (LAX). This section of Sepulveda is a part of California State Route 1. The tunnel was the first tunnel in the United States to run under an airport runway. The road has six lanes (three in each direction) along with six turnouts, each large enough to hold three cars, for vehicles that break down in the tunnel.