The latest truck safety data are in, and they show continued improvement. The number of large trucks involved in fatal crashes dropped 31% between 2007 to 2009, from 4,633 to 3,215, said the Federal Motor Carrier Safety Administration in a new report.

The number of large trucks in fatal crashes per 100 million vehicle miles dropped 26%, while the corresponding rate for automobiles fell 17%.

The data comes from the "2009 Large Truck and Bus Crash Facts", published by the agency last month.

Of the 33,808 people killed in crashes in 2009, 3,380 or 10% died in crashes involving a truck; 15% of those killed were occupants of the truck, either the driver or a passenger.

Injury crashes showed the same progress: in the two-year period, the rate per 100 million miles for trucks dropped 26%, compared to 8% for cars.

In 2009, trucks accounted for 10% of all miles traveled and 4% of all registered vehicles. They represented 7% of vehicles in fatal crashes, 2% in injury crashes and 3% in crashes that involved only property damage.

Other key points:

* Tractor-semi trailers accounted for 61% of the trucks involved in fatal crashes and 47% of those involved in non-fatal crashes.

* Doubles accounted for 3% of trucks involved in both fatal and non-fatal crashes. Triples accounted for 0.1%.

* Of the trucks involved in fatal crashes, 3% were carrying hazmats.

* 2% of the truck drivers in fatal crashes were legally intoxicated, compared to 23% of car drivers.

* Police reported that 82% of the truck drivers involved in fatal crashes were wearing their seat belts. The rate for car drivers was 63%.

* Police reported driver-related factors such as speeding or failure to stay in lane in 31% of the fatal truck crashes. The rate for car drivers was 62%.