The rest of the highway was unnumbered, despite being closely paralleled by C37 south from the Sumner Tunnel.

The Sumner Tunnel was opened in 1934.

The cab plunged into the Sumner Tunnel.

In 1961, the Callahan Tunnel opened, paralleling the older Sumner Tunnel.

It is within close proximity of the entrance to the Sumner Tunnel, which motorists take to downtown Boston.

Finally he was inching his way through the massive traffic that led into the Sumner Tunnel.

The exit to the Sumner Tunnel, the short way into town, was closed to all but taxi cabs and buses.

The Sumner Tunnel, which runs from the airport to downtown Boston, is the worse off of the two.

Repairs on the Sumner Tunnel are unlikely to begin until next summer because a plan must be developed, Mr. Romney said.

Two additional lanes are cantilevered outside the cables, which carry northbound traffic from the Sumner Tunnel and North End on-ramp.