Police are investigating a traffic crash involving a county Hele-On bus early this morning, along Mamalahoa Highway (Route 19) in Laupahoehoe that sent 22 people to the hospital.

At 4:56 a.m., Hamakua patrol officers responded to the area of the 25.5 mile marker after the bus went through a guardrail down an embankment on the makai, ocean side, of the highway.

Police determined that the bus had stopped at the Laupahoehoe Scenic Lookout to pick up passengers. The driver, a 66-year-old Hilo man, reported that he had placed the bus in park and walked toward the rear of the vehicle to check for available seating, when the bus began rolling backwards onto the highway, went through a guardrail and down an embankment, coming to rest on its passenger side.

Hawaii Fire Department personnel examined the driver and 22 passengers at the scene. All 22 passengers were transported by multiple ambulances to Hilo Benioff Medical Center for further evaluation.

The most serious injury reported was a minor laceration to the hand of an elderly male passenger.