(CBS) — The CTA has paid more than $50 million dollars over past 10 years for accidents caused by bus drivers – some killing pedestrians, others leaving victims seriously disabled.

2 Investigator Pam Zekman found serious questions about whether some of the drivers should have been behind the wheel.

“It was the most excruciating painful thing I had ever experienced,” says Amy Koplin, recalling the night she was struck by a CTA bus.

The accident happened as Koplin crossed Ohio at Michigan Avenue in Chicago. Doctors repaired her crushed feet, but she still suffers from a severe pain syndrome.

“It will be for the rest of my life,” Koplin says.

The CTA settled her suit for $6 million.

Before the accident, bus driver Ramona Spencer got eight tickets for moving violations, including a DUI, while driving her personal vehicle.

“That moment in time should have been when the CTA fired her on the spot. Instead, she continued to drive,” says Koplin’s attorney, Lawrence Ruder says.

Even before the CTA hired Spencer, she’d received six moving violations, including speeding and an improper turn. She had also been involved in two personal-injury accidents that were settled for $55,000.

“That should have been the ultimate red flag,” Ruder says.

CBS 2 reviewed 45 cases involving multiple drivers that cost taxpayers more than $50 million for 39 injuries and six fatalities.

“We want there to be no accidents, that is always our goal,” CTA spokesperson Tammy Chase says. “Can we do more? Absolutely.”

Another woman crossing Halsted Street at 18th was struck and killed by a turning CTA bus.

Martha Gonzalez died from her injuries.

Her fiancé, Andrew Kudelka, and their son, Max, sued the CTA and the bus driver, Frankie Myles, for negligence.

“His negligence was that he failed to keep a proper lookout, he was distracted,” attorney Thomas Power says.

While working for the CTA, Myles got 14 tickets in his personal car, including six for speeding. Plus, he had six accidents while driving a bus. Myles was obligated to be retrained.

“Apparently they didn’t train him very well,” Power says.

The CTA settled that case for $4.3 million.

Zekman asks Chase, the CTA spokesperson: “Both of these drivers, after the accidents, were put back on the street. Why?”

Chase: “Retraining was in order — that was the most important.”

Both before and after hiring, the CTA relies on the Illinois Secretary of State to see if that agency suspended a driver’s license. The CTA claims not to have the resources to check court records, like CBS 2 did.

Tell that to Amy Koplin, the pedestrian whose feet were crushed.

“Something needs to be done,” she says.

Bus driver Ramona Spencer, who was not terminated for her driving record, was fired for excessive absenteeism. She denies hitting Amy Koplin, saying Koplin “ran into the bus and the bus had the right of way.”

Bus driver Frankie Myles has retired and declined to comment.

The CTA says neither of the bus drivers had driving histories that met the CTA’s internal standards for termination. The question is whether those standards are tough enough to protect the public.