After soaring in the first six months of last year, traffic deaths this year have declined slightly but still are well above the all-time low set in 2011, according to statistics released Tuesday.

The National Safety Council estimated that 18,680 people died in crashes through June this year and 2.1 million people were seriously injured. There have been 250 fewer deaths this year than in the same period in 2016.

“The price of our cultural complacency is more than a hundred fatalities each day,” said Deborah A.P. Hersman, president of the National Safety Council and former chairman of the National Transportation Safety Board. “Although the numbers may be leveling off, the road to zero deaths will require accelerating improvements in technology, engaging drivers and investing in our infrastructure.”

The council estimated that crashes this year have cost $191 billion in deaths and injuries.

The council’s report comes three weeks after a preliminary report by the agency that Hersman once chaired concluded that speeding causes as many crashes as drunken driving.

The NTSB found that speeding contributed to 112,580 highway crash deaths between 2005 and 2014. By contrast, 112,948 people died during the same period in crashes where alcohol was involved.

“You can’t tackle our rising epidemic of roadway deaths without tackling speeding,” NTSB Chairman Robert L. Sumwalt said. “Speed kills. This study examines how it kills and what actions can be taken to save lives and prevent speeding-related crashes.”

The NTSB study, a preliminary portion of which was released in July, points out that “speeding has few negative social consequences compared to the consequences of an arrest or conviction for driving under the influence,” despite the fact that most drivers recognize the danger.

The NTSB recommended that seven states that prohibit automated speed cameras and 28 states that lack laws on them “remove barriers to the use of automated speed enforcement.”

National Safety Council tracking data shows that crash deaths spiked early in the 21st century before taking a nosedive when the recession took hold, costing jobs and keeping people off the roads. Combined with improvements in highway and automotive safety features, those lean years kept traffic deaths steady for several years before they shot up sharply last year.

That increase was attributed to a more buoyant economy and lower gas prices that led to a 1.7 percent increase in miles driven in the past year. The safety council estimated that up to 40,000 people were killed in crashes in 2016, a 6 percent bump over 2015 that was the greatest percentage increase in 53 years.

The council data differs from the fatality numbers compiled by the National Highway Traffic Safety Administration. Both sets of numbers are accurate.

NHTSA counts those traffic deaths that occur on public roadways within 30 days of a crash. The safety council includes fatalities in public and nonpublic locations, including in parking lots, parking structures and private driveways and on private roads. It also includes those who die within 100 days after suffering an injury in a crash.

The number of people killed reached a record low of 32,675 in 2014, according to NHTSA statistics.