Complaining about another state's drivers is something of a national pastime. Here in Washington State, Oregon drivers are the target of our wrath; in Illinois, where I grew up, we picked on Missouri drivers. (The "Show Me State"? Sure, if they mean, "Show Me How to Drive.")
It is absolutely true that driving skill differs across state borders, sometimes substantially. The most pertinent statistic in this regard is traffic fatalities. (For the following analyses, I utilized the CDC's WISQARS database and visualization tool. All data are from 2016.)
In the deadliest state (Mississippi, 25.3 fatalities per 100,000 people), a person is more than five times as likely to be killed in a car accident than in the least deadly state (Rhode Island, 5 fatalities per 100,000). (See map and bar graph below.)
It is noteworthy that the three deadliest states (Mississippi, Alabama, South Carolina) are all in the Deep South, while the three safest states (Rhode Island, New York, Massachusetts) are all in the Northeast. The data do not explain why this is the case, but there appears to be an urban/rural divide in terms of traffic safety, with rural states being more dangerous.
An analysis by age shows a U-shaped graph: Young people and old people are the likeliest to die in a car crash. This makes sense because younger people tend to be inexperienced and more reckless, while older people tend to have slower reflexes.
Analyzed by race/ethnicity, whites and blacks have roughly the same likelihood of dying in a vehicle accident, while Native Americans have a notably higher risk and Asians have a notably lower risk.
Finally, the timeless question of whether men or women are better drivers can be answered definitively using fatality data. Women are, by far, the safer drivers.
The data don't lie. Using traffic fatality statistics, America's worst drivers are likelier to be men or people who live in the South, are either young or old, or identify as Native American. America's best drivers are likelier to be women or people who live in the Northeast, are aged 35 to 75, or identify as Asian.
Source: CDC WISQARS