His latest investigation found an "outdated" and confusing system for reporting and monitoring drivers with potentially unsafe medical conditions such as uncontrolled hypoglycemia, the ombudsman said.
Forms and medical information are archaic, doctors aren't reporting at-risk patients and, in some cases, the ministry either isn't getting all the information or isn't acting on it, he said.
"Right now, what's happening in Ontario is bureaucratic calamity mired by general chaos," he said.
Vehicles in the hands of drivers with uncontrolled or unaware hypoglycemia are "uncontrolled" missiles that are "a huge danger to the public," Marin said.
"The public doesn't realize really the extent to which they are vulnerable on our roads and highways," he said.
According to the Ministry of Transportation, there were 7,336 drivers who were considered insulin dependent in 2010, Marin said. It's estimated that 25 per cent of them will suffer hypoglycemic episodes — low blood sugar that can cause dizziness, drowsiness and vision changes — without being aware of it.
His report focused on a 2009 car crash that killed three people, caused by a diabetic Hamilton man who was experiencing severe uncontrolled hypoglycemia.
Allan Maki, 40, had started experiencing episodes of uncontrolled hypoglycemia in 2002. He renewed his driver's licence in 2007, but got an outdated form that didn't ask specific information about his use of insulin, the report said.
Maki ate a snack before the accident because his blood sugar level was low, but didn't wait to confirm that his condition was stable before getting behind the wheel, it said.
"This is more than a time bomb waiting to explode because it did explode, causing the death of three people," Marin said.
The high school teacher was convicted in 2011 of dangerous driving causing death, but the Ministry of Transportation failed to suspend his licence until 18 months after the crash.
Fortunately, his bail conditions barred him from driving, Marin said.
The emergency room doctor and police both sent reports to the ministry following the accident, but it couldn't find them, he said.
The ministry did get in touch with police about Maki's criminal charges in 2010, but they weren't from the department that deals with medical reviews, the report said. His licence wasn't suspended until nine months later.
Ontario doctors are required and paid $36 to report patients to the ministry if they have medical conditions that might make it unsafe for them to drive, Marin said.
"But the requirement is of no value if it's not followed up, or if it's too confusing, or if it just amounts to paperwork that is just shuffled lost or forgotten," he said.
The ministry shoulders most of the blame for letting the system slip, but the medical community has to take it more seriously and police need to be more diligent, he said.
The government has agreed to implement all of his recommendations to improve the system, Marin said.
Some of his 19 recommendations are part of a program review that's currently underway, while others have already been acted on, Transportation Minister Glen Murray said in a statement.
Marin recommendations include extending mandatory medical reporting requirements to nurse practitioners and other health-care professionals.
He also wants Ontario to set up a system where whistleblowers can report potentially unsafe driving, just like Alberta, British Columbia and Saskatchewan. It can prompt the government to make inquiries to confirm that someone is fit to drive.