TUSCALOOSA, Ala. — As a pilot study of the impact of lap-shoulder belts on school buses enters its final year, national and state transportation safety agencies are awaiting the results.

The study, conducted by the University of Alabama’s University Transportation Center for Alabama, has 12 new school buses at 10 school districts equipped with different types of lap-shoulder (or three-point) belts.

According to the university, the project involves four areas of research: a review of national experiences and trends, alterations needed to the Alabama bus fleet if seat belt use is adopted, analysis of Alabama school bus crash data and a cost-benefit analysis.

The buses in the study each have four ceiling-mounted video cameras, allowing the research team to gather data on the level of restraint use, review the percentage of students using the belts and the percentage of students using the belts properly, and investigate whether using the belts keeps students from moving into the aisle and out of the protective compartment provided by the seats.

Researchers said that the camera data will also gauge the benefit of having a bus aide to monitor students, and time devoted to buckling at each stop will be tracked.

“The first two years of our study have given us insight into the basic pattern of school bus seat belt use by Alabama’s schoolchildren,” said Dr. Jay Lindly, director of the University Transportation Center for Alabama. “The third and final year will allow us to vary some of the basic parameters of the study to see how that affects results. For example, does changing the bus driver on a route affect seat belt usage, or does adding an aide to a route affect seat belt usage?”

Dr. Dan Turner, professor of civil engineering and the principal investigator of the research team, said that detailed results will not be released until the study is completed. However, the team did say that the number of students wearing the belts properly has risen during the past year, and that there has been an increase in positive public perception regarding the installation of the belts.

The University of Alabama said that it is the first institution to carry out a large-scale scientific study of seat belts on school buses. Accordingly, the National Highway Traffic Safety Administration, the National Transportation Safety Board and other agencies have contacted the research team and are awaiting the results.

The study was prompted by the 2006 school bus crash in Huntsville, Ala., in which four students were killed.