Complex sentence: For some time after the Big Dig ceiling collapse in 2006, the SL1 used a closer entrance ramp normally reserved for the Massachusetts State Police, however use of this shortcut was stopped for safety reasons after the affected sections of roadway were reopened for Silver Line use.
Split into simpler sentences: For some time after the Big Dig ceiling collapse in 2006, the SL1 used a closer entrance ramp normally reserved for the Massachusetts State Police. However, use of this shortcut was stopped for safety reasons after the affected sections of roadway were reopened for Silver Line use.