The puzzling rise coincides with an increase in sophisticated safety equipment offered on many vehicles and public-service campaigns that warn about the dangers of distracted, drunk and drowsy driving.
An estimated 26,000 people died in vehicle crashes in the first nine months of 2015, a 9.3 percent increase from a year earlier and the most since 2008. Complete figures will be released this spring.
U.S. regions nationwide showed increases ranging from two to 20 percent, NHTSA said.
"We're seeing red flags across the U.S. and we're not waiting for the situation to develop further," said NHTSA Administrator Mark Rosekind in a statement. "It's time to drive behavioral changes in traffic safety and that means taking on new initiatives and addressing persistent issues like drunk driving and failure to wear seatbelts."
Federal safety regulators are kicking off regional safety summits that will look at new approaches to cutting road deaths.
Edmunds says: The feds will take a hard look at the human factors behind 94 percent of crashes.