Four children died in school bus loading and unloading accidents in the U.S. last school year, according to the latest survey of such fatalities.

Three of those four children were fatally struck by school buses — two at the front of the bus, one at the back. One student was killed by a passing vehicle.

The national school bus loading and unloading fatality statistics are collected annually by the Kansas State Department of Education’s (KSDE’s) School Bus Safety Unit. The newly released edition covers the 2015-16 school year.

The survey shows that the four school bus danger zone deaths occurred in four states: Alabama, Florida, Kentucky, and Nevada. All other states reported no such fatalities, except for Mississippi, which chose not to participate in the survey.

Three of the four children who died in the 2015-16 incidents were age 5 or younger. One was 16 years old. All four were male.

The total of four fatalities in 2015-16 ties with the previous year’s total of four as the lowest in the 46 years on record. During the past five years, there has been an annual average of about seven loading and unloading fatalities.

Here are details on the 2015-16 danger zone incidents from the KSDE report:

• In Alabama, three students were loading the school bus. Two of the children boarded the bus. However, a 5-year-old had dropped something and stopped to pick it up. The child was struck and killed by the bus.

• In Florida, a 16-year-old boy was crossing the street to load onto the school bus. The stop arm and eight-way red lights were activated. An oncoming vehicle didn’t stop, and the student was struck and killed.

• In Kentucky, a 5-year-old boy, who had unloaded from the school bus, was struck and killed by the left front wheel of the bus.

• In Nevada, a student riding the school bus was being dropped off at his home. The student’s sibling crawled under the school bus and was killed as the bus pulled away.

The KSDE school bus loading/unloading survey is a collection of fatality accident records provided by the state agencies responsible for school transportation safety and/or accident records. On-board fatalities are not included.

The survey is described as “an effort to alert individuals and organizations of the dangers involved in loading and unloading school children. … It points out the continuing need for forceful, advanced instruction to school bus drivers and students, as well as the need to increase our efforts to thoroughly inform the driving public about the requirements of the school bus stop law."

To view the full report for 2015-16 and previous school years, go to the KSDE website.