Backhoe rolls off truck on I-495 in Southbororough, killing one

From the Massachusetts State Police press release:

At 1:15 p.m. today, Troopers assigned to the Massachusetts State Police Barracks in Millbury responded to a crash on Route 495 southbound, south of Simarano Drive (Exit 23C), in Southborough, that resulted in one fatality and serious injuries to three people.
Preliminary investigation by Trooper Craig Brabham indicates that a 2010 Freightliner truck towing a 2007 Case backhoe on a trailer, was travelling south on Route 495 when the backhoe rolled off of the trailer and landed on top of a 2000 Toyota Sienna operated by Yingzi Wang, 42, of Westford.The Toyota and the backhoe travelled down an embankment approximately 20 feet and came to final rest with the backhoe on top of the Toyota. The four occupants of the Toyota were trapped inside.
Xjaoyun Jiang, of Westford, who was a backseat passenger in the Toyota, was pronounced deceased at the scene. The most specific information that family members can provide is that she was in her 70’s.  The operator of the Toyota was transported by medical helicopter to UMass Medical Center. Two children, a 10-year-old boy and a 13-year-old girl, who were also passengers in the Toyota, were transported by ambulance to UMass Medical Center.  The operator of the truck, Jeffrey Fisher, 49, of Coventry, Rhode Island, was not injured.  The truck is owned by National Grid.
The crash remains under investigation by Troop C of the Massachusetts State Police with the assistance of the State Police Collision Analysis and Reconstruction Section, the State Police Commercial Motor Vehicle Enforcement Section and the State Police Crime Scene Services Section. Troopers were assisted at the scene by the Southborough and Westborough Fire Departments and the Department of Transportation’s Highway Division.
The two right travel lanes and the breakdown lane were closed for approximately 6 hours and traffic was delayed for approximately 3 ½ miles. All lanes were opened at 8:00 p.m.