Next time someone cuts you off in traffic, fails to signal a lane change and nearly sideswipes your car, or travels 40 on the highway, go easy on them. They might not be able to change.

Jalopnik reports, "According to a study published in the neurological science journal Cerebral Cortex, there's a gene responsible for bad driving." Up to 30 percent of America's drivers may have it.

Eureka Alert explains, "People with a particular gene variant performed more than 20 percent worse on a driving test than people without it." The study, performed by neuroscientists at the University of California, Irvine, looked at people who carry a gene variant that "limits the availability of a protein called brain-derived neurotrophic factor during activity. BDNF keeps memory strong by supporting communication among brain cells and keeping them functioning optimally." Researchers asked 29 people (22 of whom carried the variant) to "drive 15 laps on a simulator that required them to learn the nuances of a track programmed to have difficult curves and turns. Researchers recorded how well they stayed on the course over time." They repeated the same test four days later. "Results showed that people with the variant did worse on both tests than the other participants, and they remembered less the second time."

Don't bother trying to steal a hair sample from the bad driver in the family, however. Eureka Alert notes, "A test to determine whether someone has the gene variant is not commercially available."

If you're in the market for a new car, check out the U.S. News rankings of this year's best cars as well as this month's best car deals.