"We've had just two nonfatal accidents there since they completed that work."

The system also raises damage limits for nonfatal accidents, and simplifies rules on shipping cargo, allowing more electronic records.

And parents are concerned that the shortage is compromising safety, though it is difficult to tell, because there are no statistics on nonfatal accidents and other school bus problems.

Reporting of nonfatal accidents is spotty, he said, and for fatal accidents the states lack a uniform classification system that distinguishes one multiple-trailer vehicle from another.

Among drivers of automobiles, long-haul trucks and even buses, sleepiness is believed to be responsible for a large share of fatal and nonfatal accidents.

The mine had three nonfatal accidents in 1920.

However, at that site, 1 in every 254 jumps over that period resulted in a nonfatal accident.

The figures may be incomplete because the Coast Guard estimates it receives reports on only 5 percent to 10 percent of all nonfatal accidents.

But even if death is avoided, many sandhogs have scars, and grisly stories, from nonfatal accidents.

The CL-600 had 0.88 nonfatal accidents, and 0.18 fatal accidents, for every 100,000 flying hours, he said, compared with industrywide averages of 1.17 and 0.38.