Adult drivers and passengers in America’s most rural counties had motor-vehicle death rates that were three to 10 times higher than those in the most urban counties, according to 2014 data released by the U.S. Centers for Disease Control and Prevention (CDC).

Overall, the study found lower seat belt use, higher death rates and a higher proportion of drivers and passengers who were not buckled up when fatal crashes occurred in rural areas of the nation.

“We know seat belts save lives,” said CDC Director Brenda Fitzgerald. “These findings remind us that no matter what kind of road you are traveling on, it is important for everyone to buckle up every time on every trip.”

The agency used data from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System to identify passenger-vehicle occupant deaths among adults 18 years or older. Data from the CDC’s Behavioral Risk Factor Surveillance System was used to estimate how often drivers and passengers used seat belts.

The study found that death rates for adult drivers and passengers grew as areas became more rural. Death rates per 100,000 population varied:

• In the West, from 3.9 in the most urban counties to 40 in the most rural counties
• In the South, from 6.8 in the most urban counties to 29.2 in the most rural counties
• In the Midwest, from 5.3 in the most urban counties to 25.8 in the most rural counties
• In the Northeast, from 3.5 in the most urban counties to 10.8 in the most rural counties

Similarly, the proportion of drivers and passengers who were not buckled up at the time of a fatal crash was 44.4 percent in the most urban counties, compared with 61.3 percent in the most rural counties.

The study also found that seat belt use in rural areas was significantly higher in primary-enforcement states (where an officer can ticket a driver  or passenger for failure to use seat belts) than in secondary-enforcement states (where an officer can issue a ticket for failure to use seat belts only when another violation has occurred).

“Although we know motor-vehicle crash-related deaths have been historically higher in rural areas, this study shows that the more rural the area, the higher the risk,” said Laurie Beck, an epidemiologist in the CDC’s Division of Unintentional Injury Prevention. “It also helps us confirm what works to prevent these crash deaths, such as primary-enforcement seat belt laws and seat belt use. These new findings will allow us to better target our prevention efforts as we work toward zero road-traffic deaths in the U.S.”