Bad drivers may in part have their genes to blame, suggests a new study by UC Irvine neuroscientists. People with a particular gene variant performed more than 20 percent worse on a driving test than people without it – and a follow-up test a few days later yielded similar results. About 30 percent of Americans have the variant. “These people make more errors from the get-go, and they forget more of what they learned after time away,” says Dr. Steven Cramer (pictured), neurology associate professor and senior author of the study, published recently in the journal Cerebral Cortex.