Under federal law, commercial drivers may not use alcohol within four hours of going on duty. Those drivers found to have any measurable amount of alcohol in their system must be placed "out of service" for 24 hours, which means they are not allowed to operate a commercial vehicle during that time.
The Federal Motor Carrier Safety Administration has set the blood alcohol threshold for driving under the influence at 0.04% for commercial drivers, including school bus drivers. States have established a 0.08% DUI standard for regular drivers, except Utah, where it is 0.05%.
The council also is urging school districts to embrace drug-free-workplace policies that educate employees -- particularly supervisors -- about the signs and symptoms of impairment and addiction. If supervisors spot something wrong, they can respond immediately, Vogel said.
"School bus drivers are safety-sensitive positions," she said. "School districts should be empowered to set additional requirements, such as visual check-ins by supervisors."
While federal regulations require that commercial drivers, including school bus drivers, be tested if there is "reasonable suspicion" they are using alcohol or drugs on duty, that relies on someone eyeballing the driver, which doesn't always happen, Stateline found.
In large school districts with hundreds of buses, inspecting every driver would be difficult, and in some areas, particularly rural ones, drivers take their buses home.
Cathy Chase, president of Advocates for Highway and Auto Safety, a Washington, D.C.-based nonprofit alliance of health and safety groups and insurance companies, said Stateline's findings have "brought much-needed focus to an issue which is likely underreported and in need of more careful scrutiny."
The group is recommending that school buses be added to a bipartisan bill pending in Congress that would require new motor vehicles to be equipped with "advanced passive alcohol detection software," technology that automatically detects whether drivers are intoxicated through their breathing or touch.
"If we get this technology into school buses," Chase said, "there would be an added sense of security for parents that their children would be protected."
Chase's group also wants states, as soon as possible, to start using a new federal drug and alcohol clearinghouse that contains information about drivers with commercial licenses who have drug or alcohol testing violations and are not permitted to operate commercial vehicles.