Investigators are looking into the possibility that Russell Weller, 86, hit a Mercedes after leaving a post office, then sped less than a block west toward the street market, California Highway Patrol spokesman Tom Marshall said. Details about the Mercedes crash were not immediately available.
"We're trying to do two things: determine first of all that he hit the Mercedes, and two, what his motivation was for leaving if he did hit it," Marshall said. "He could have been confused, he could have been scared and tried to get away, we just don't know at this point."
Like Weller's Buick sedan, the Mercedes has been impounded and is being examined, Marshall said.
Weller's attorney, Jim Bianco, released a statement Wednesday saying the farmers market crash was an accident. He and another attorney for Weller did not return calls for comment Friday.
Police have said Weller told them he didn't realize until too late that Arizona Avenue, crammed with pedestrians and produce Wednesday, was closed to traffic. They said Weller believes he might have hit the gas instead of the brake as he tried to stop.
Witnesses said Weller's car sped down the entire length of the open-air market, knocking down stalls, scattering produce and hitting as many as 50 people. Ten victims, ranging in age from 7 months to 78 years, were killed.
At least 13 people remained hospitalized Friday, three of them in critical condition. Officials at two of the hospitals where victims were taken did not immediately return calls seeking the number of patients still in their care.
Marshall said it could take weeks for the CHP and Santa Monica authorities to complete their investigation. Santa Monica police Lt. Frank Fabrega said his department wasn't releasing any information about the investigation.
The crash has raised questions on whether more stringent regulations may be required for elderly drivers.
Dr. Robert Wang, the head of Geriatric Medicine at Century City Hospital in Los Angeles, said questions about driving for the elderly focus on sensory perception, mobility, reaction time and a tough area to test, cognition.
"Do you understand the situation you're in? Do you recall that someone is behind you on the left side or the right side? If you don't remember those things, you're going to get yourself into a dangerous situation," he told CBS News Early Show co-anchor Julie Chen.
By the year 2030, the National Institute on Aging estimates, 25 percent of all drivers will be older than 65, and the Insurance Institute for Highway Safety says that 25 percent of all fatal traffic crashes will involve drivers 65 or older by that same year.
Wang says traffic safety is important for seniors themselves as well as others because studies have shown when older drivers do get into accidents, they are more easily hurt and less likely to survive their injuries. Road accidents are leading cause of injury-related deaths in the population over 65. The fatality rate for drivers over 85 is nine times higher than the rate for drivers 25-69 years old.
Wang explains that problems with vision, perception, hearing, joint mobility, response time, dementia and motor skills increase with age. These factors all may cause driving problems.
Diabetes can numb the legs and feet, making it difficult to know if you're braking or accelerating properly, he says. Also, arthritis can hamper turns and traffic checks. Seniors may have trouble judging spatial relations and juggling more than one task.
Wang says the issue of road-testing seniors differently from other age groups is very controversial. Many states do have age-based rules such as requiring those older than 65 or 70 to renew licenses in person, renew them more often or pass road and vision tests.
Laws typically require a minimum vision requirement for a driver's license and some states impose behind-the-wheel testing if doctors or others report concerns about a driver's physical or mental limitations. If necessary, restrictions can be placed on people's licenses. The restrictions include measures such as annual testing, limiting driving to daylight hours or in-town driving only.