The Lieutenant William F. Callahan Jr. Tunnel (colloquially Callahan Tunnel) is one of four tunnels, and one of three road tunnels, beneath Boston Harbor in Boston, Massachusetts. It carries motor vehicles from the North End to Logan International Airport and Route 1A in East Boston. Ordinarily, this tunnel is only used to carry traffic out of the city, and with the completion of the Big Dig it only collects traffic from I-93 southbound (right after traffic merges from Storrow Drive) and downtown Boston; northbound traffic uses the Ted Williams Tunnel. As of 2016, a toll of $1.50 is charged for non-commercial two-axle vehicles with a Massachusetts E-ZPass, while non-Massachusetts E-ZPass holders are charged $1.75. Vehicles without E-ZPass are charged $2.05 through MassDOT's Pay By Plate MA