Because the pickup truck that collided with a group of motorcyclists in New Hampshire last month had a gross vehicle weight rating under 26,001 pounds, its driver was not required to have a CDL.

That’s one of the findings in a preliminary report issued by the National Transportation Safety Board (NTSB), which is investigating the June 21 accident that killed seven motorcyclists and injured three others. The 23-year-old driver of the pickup truck, which was towing an unladen flatbed trailer at the time of the incident, was not injured.

The collision occurred on Gorham Hill Road (US Highway 2), a two lane road divided by a double yellow centerline with a posted speed limit of 50 mph. The pickup truck crossed the center of the road and collided with the approaching motorcycles. After the crash, the pickup truck continued across the eastbound lane and came to rest on an earthen embankment next to the eastbound shoulder. A fire broke out after the crash.

The NTSB investigation into the incident is ongoing as the agency focuses on determining the probable cause, with the intent of issuing safety recommendations to prevent similar crashes. The NTSB is working in partnership with the New Hampshire State Police, state licensing agencies in New Hampshire and Massachusetts, the Federal Motor Carrier Safety Administration, and the US Department of Transportation Office of Inspector General.