WASHINGTON, D.C. — A new government report on school bus safety analyzes 15 years of crash data and surveys states’ requirements for school bus inspections and driver training.

The Government Accountability Office (GAO) report, released on Thursday, was required by the Fixing America's Surface Transportation Act, the highway bill passed in December 2015. GAO is the investigative arm of Congress

Over the past year, GAO examined fatal crashes involving school buses from 2000 to 2014 and federal and state school bus regulations. Overall, the GAO report shows a relatively low incidence of fatal school bus crashes and an abundance of regulations, some of which vary from state to state.

“School buses have a strong safety record, but school bus crashes with fatalities and injuries still occur and are often high-profile, since they involve precious cargo — the nation’s schoolchildren,” GAO said in the report. “Thus, government agencies, student transportation groups, and others strive to further improve the safety of school buses.”

For its school bus crash analysis, GAO used two sets of data, from the National Highway Traffic Safety Administration and the University of Michigan Transportation Research Institute. GAO found that from 2000 to 2014, there was an annual average of 115 fatal crashes that involved school buses. Those made up 0.3% of the 34,835 total fatal motor vehicle crashes on average each year.

According to the GAO analysis, the school bus driver was determined to be a contributing factor in 27% of the fatal school bus crashes, while the school bus itself (for example, a vehicle defect) was cited as a contributing factor in less than 1% of the crashes.

"School buses are very safe," Susan Fleming, director of GAO's physical infrastructure team, said in an email to SBF. "Federal laws and regulations set requirements for certain aspects of school bus safety, and state laws and regulations in many cases go beyond the federal requirements."

Another noteworthy crash-related finding from the report: “School bus crashes constituted less than 1 percent of all crashes in 6 of our selected states for which annual crash reports included a section on school bus crashes.”

The GAO report also explains federal oversight of pupil transportation, including the CDL requirements for school bus drivers and the federal motor vehicle safety standards that apply to school buses.

GAO also identified differences from state to state for some pupil transportation requirements. For example, the report found that all 50 states require school bus inspections, although there are variations in the frequency of the inspections and the agency conducting them.

In the realm of driver training, GAO found that 44 states require entry-level training and 44 states require refresher training for all school bus drivers. As with inspection rules, the frequency, length, and other details of the training vary across states.

The report notes that the Federal Motor Carrier Safety Administration recently established national minimum training standards that will apply to entry-level commercial vehicle operators, including school bus drivers.

The GAO report also provides details on state requirements for the maximum age and seating capacity of school buses.

To view the GAO report, go here.

The release of the report, which was in the works since February 2016, came a day after three congressmen requested a hearing on school bus safety in response to recent high-profile crashes in their states.