Inspectors found nothing to indicate a threat to public safety or that any of the structures inspected would be insecure, said Thomas Tinlin, Massachusetts Dept. of Transportation Highway administrator, in a Feb. 13 statement.

“Out of an abundance of caution, crews performed cautionary maintenance at 65 sites,” he said. They examined manhole covers, sewage drainage-system grates and covers for electrical panels.

Crews made visual inspections, drove their vehicles over manhole covers and struck each metal cover with various tools, to see if there was any give or shift.  “At the smallest amount of movement, crews took action in welding covers,” Tinlin said. “No covers at any of the 919 locations were deemed possible for immediate failure.”

MassDOT will continue to collaborate with the Massachusetts State Police, the Suffolk County District Attorney’s Office and MassDOT’s inspection contractor AECOM to determine the root cause of the incident. The 200-lb storm drainage cover that killed Clavette was last inspected by AECOM in 2014 and found to be in very good condition.

What caused the cover to become dislodged is part of the ongoing investigation by the Massachusetts State Police, with assistance from its Collision Analysis and Reconstruction department and Crime Scene Services and Suffolk County's detective unit.

At the Massachusetts State Police headquarters in Framingham, state trooper Paul Sullivan estimated it would be at least a month until there is any conclusion. “We will be working on the car [accident] reconstruction and running calculations to understand the mathematics of what happened,” he said.