The Houston school board has voted to require students to use three-point seat belts on buses that have them.
The Houston Chronicle reports that the requirement does not apply to buses that have only lap belts. The newly adopted rules urge students to use lap belts, but do not require it.
The district has about 1,100 buses; about 430 have lap belts and 150 have three-point belts, which strap across the waist and shoulder.
The new seat belt rules are being adopted nine months after two district students died and two others were seriously injured in after their bus plummeted off Interstate 610. The bus had lap belts, but the four students on board were not wearing them.
In response to the crash, Houston school officials decided that when it came time to replace buses, they would buy ones outfitted with three-point seat belts.
In deciding not to make lap belt use mandatory, district officials say that under their interpretation of state law, students must buckle up only if a school bus has three-point seat belts.
Most school buses across the nation are not equipped with seat belts, but last year, the administrator of the National Highway Traffic Safety Administration recommended for the first time that school buses be equipped with three-point seat belts.
The new Houston rules say that students who persistently violate the district's bus rules could be suspended or lose their riding privileges.