Expect significant travel delays From July 5 to August 5, the Sumner tunnel will be fully closed to traffic. The tunnel will close at 12:01 a.m. on Friday July 5 (immediately after July 4) and reopen by 5 a.m. on Monday August 5.. MGH-East Boston Health Center shuttle will be most affected. Please plan your trip ahead. We thank you for riding and apologize for any inconvenience.