What does it take to keep bad drivers off the road?

How easy is it to get a license in CA? A bus driver in a fatal crash had a history of arrests, tickets, had his license revoked, just got it back, had a history of substance abuse and then was put behind the wheel of a bus.

The articles states:

• Watts was arrested as he lay critically injured in his hospital bed. His mother said he had wrestled with drug and alcohol problems, was jailed several times on drug charges and had smashed a car carrying a friend into a tree a few years ago, though neither was seriously hurt.
• He was a longtime truck driver, but had been unable to find a trucking job since being released from jail on a domestic violence charge six months ago, his mother said.
• Chaney Mae Watts said she believed the crash came on her son's first day behind the wheel of the bus after several training trips watching the owner drive. She and her husband told their son they were uncomfortable with him driving a vehicle that carried people instead of cargo.
• "He wasn't the best driver," she said. "He knew we didn't want him to drive."

The DMV has struggled with the problem of licensing most recently setting some tougher standards that appear to target seniors involving a revised vision exam as well as memory and reflex assessments. However its had a problem keeping people with a bad record and impaired driving record off the road. In addition many people with revoked licenses still drive so the question remains what other form of electronic monitoring can be used on bad drivers.