The medical examination that school bus drivers must pass before being permitted to transport children would not reveal a seizure disorder unless the person voluntarily disclosed it or showed signs of a neurological problem, said doctors familiar with the exam.
The medical history of a Baltimore school bus driver could become a factor as investigators determine what caused his bus to crash into a transit bus in Southwest Baltimore on Nov. 1, killing him and five other adults. A spokesman for the National Transportation Safety Board said that if investigators learn the driver was suffering a seizure — he is believed to have a history of them — their report may include policy recommendations to help prevent similar accidents in the future.
The driver physicals involve checks for vision or hearing impairment and analysis of urine samples for conditions such as diabetes or kidney disease. But a history of seizures would only come to light if the driver included it on a medical history list, which they sign under penalty of perjury, or showed symptoms such as delayed reflexes.
Passenger safety relies on an assumption that drivers are honest, said Dr. Clayton Cowl, chairman of the division of preventive, occupational and aerospace medicine at the Mayo Clinic. The medical exams are required of anyone operating a commercial vehicle, and aircraft pilots and ship captains are subject to similar vetting.
"Ultimately it goes back to the driver making sure that every time they get behind the wheel that they're fit to drive," Cowl said. "When you're doing it for your livelihood, obviously you're conflicted from the start."
Federal and state lawmakers and transportation safety advocates said they are eager to see if the NTSB report recommends any changes in law or regulations.
"If any shortcomings in our safety regulations are found, we must work to resolve them immediately to prevent accidents and save lives in the future," Rep. Elijah E. Cummings said in a statement.
Glenn Chappell, a driver for a Baltimore City Public Schools contractor, was on his way to pick up students for Dallas F. Nicholas Elementary School when his bus rear-ended a Ford Mustang, crossed into oncoming traffic and rammed into a Maryland Transit Administration bus Nov. 1, police said.
Chappell and five people aboard the MTA bus, including the driver, died. Eleven people were injured, including an aide who was the only other person on the school bus.
Investigators are looking into whether Chappell suffered a medical emergency that caused the crash, after they ruled out mechanical failure or an intentional act. Days after the crash, it came to light that after Chappell crashed his car in Ellicott City in 2014, his wife told police he had taken medication to prevent seizures.
Maryland Motor Vehicle Administration officials said that at the time of the crash Chappell had been barred since Sept. 1 from operating a commercial vehicle because a certificate testifying that he was in good health had expired. While he had not provided a new one to the MVA, he did share documentation with Baltimore schools officials that he passed a physical in June.
The medical examination required of bus drivers, or anyone operating a vehicle that carries 16 passengers or more, is designed to ensure a person is physically and mentally up to the task. Commercial driver's license-holders are required to pass the examination at least once every two years, and more often if they have a medical condition that bears monitoring, according to the Federal Motor Carrier Safety Administration, which oversees the process.
The exam begins with questions about a driver's medical history, and drivers must fill out a form indicating whether they ever had seizures, epilepsy or head or brain injuries, among other conditions. The drivers sign the form certifying that the information is "accurate and complete," and are warned that they could face civil or criminal penalties if it is not.
If a driver says they have a history of seizures, doctors typically end the examination and disqualify the driver. For anyone with epilepsy, a certificate can't be issued unless the driver hasn't had a seizure or taken seizure medication in a decade.
"We don't even finish the exam if a person says they have epilepsy," said Dr. Nellie Whitaker, a Baltimore physician who this month became certified to perform the driver physicals.
Since 2014, doctors have been required to receive special training and pass a test in order to issue the medical certificates.
Other conditions that could disqualify drivers include hearing or vision loss, narcolepsy, hypertension and diabetes, though doctors can make some exceptions.
The driver's exam tests hearing and vision. Drivers must be able to hear a whisper from 5 feet away. Their field of vision must extend 70 degrees above and below a horizontal meridian, and they must be able to distinguish red, green and amber colors.
Doctors look for scars that might indicate past heart surgeries, and they check for hernias. Drivers submit to a urine sample to check levels of glucose or detect any blood. Doctors observe the driver climbing onto and off of the examination bench, and ask them to raise their arms above their head.
It's unlikely those tests would reveal a seizure disorder, Cowl said. A driver would only be referred to a neurologist if an examiner noticed something abnormal.
"The process is only as good as the driver being honest and the medical examiner having some natural curiosity," he said.
When asked about the possibility that drivers with seizure disorders could slip through, public officials and safety advocates said they are waiting to hear the results of the NTSB's investigation, and are ready to push for reforms, if necessary.
Cummings said he and colleagues on the House transportation committee "have been fighting to ensure that commercial drivers are medically fit for duty and systems are put in place to identify individuals who may pose safety risks."
Rep. John Sarbanes said officials must use the NTSB's findings to "do everything we can to help improve transportation safety and prevent future accidents from taking place."
And state Del. Kumar P. Barve said he already is planning hearings before the transportation committee that he chairs.
"Bureaucracy failed here," Barve said of the fatal bus crash. "We have to get to the bottom of why that happened."
Charles Hood, executive director of the National Association of State Directors of Pupil Transportation Services, said that school buses are "far safer than the other ways students are transported to and from school."
But if the Baltimore crash exposes a vulnerability in the system, he said he is eager to hear any recommendations to address it.
"I am confident that the NTSB will delve into it," he said.